My partner is destroying my sanity

 My life is in a disastrous spiral toward rock bottom. I'm not gonna say that my life was great and that I was mentally or emotionally healthy before this point but I'm hitting an all time low. My girlfriend is an extremely good manipulator. She can make me question even the things I know to be facts. Things that I've seen, felt and experienced. At the start of the relationship I was completely sure that we were head over heels for each other. Every time we spent time together in the beginning she wouldn't take her eyes off me as if I was the actual center of the universe. Fast forward to now. She cheated once before and swore that it was a mistake and apologized more times than I can count. Prior to this event I noticed strange behavior. Things like purposely making sure I don't see who she's texting when she never cared before. Certain phone calls she would only answer or dial in the bathroom with the door closed and locked. Getting really irritable or affectionate in the blink of an eye. Now none of this made me feel like I was losing my mind it's what happened next. She has a 6 year old daughter and an extremely jealous ex who's the father of said daughter. Well one thing led to another and after several nasty conversations between him and I, my girlfriend and I were dealing with a cps investigation over claims of abuse from her ex. We dealt with the investigation and I had thought that everything was fine. The case workers told both of us that the investigation was going to be closed. A couple weeks later she tells me that cps suddenly changed their mind about closing the case and now they told her she has to move into a witness protection type situation until the investigation is concluded. The whole situation didn't make any sense to me but I took her word for it even when everybody I talked to about it told me the details don't add up. She was only supposed to be gone for a couple weeks to a month at the most while they supposedly finished up the investigation. After almost 6 months of being gone and an endless plethora of excuses she finally moved back in. After her being back home for a week or so I started noticing that some of the mail she brought back with her had the name and address that matched where she was living of the guy she had cheated with. Now me being suspicious of her already immediately questioned her about it. It turns out that she had been in contact with him when she swore she wasn't but she assures me that it was nothing for me to worry about she only helped him by putting some of his bills in her name to help him and avoid problems at work since they were at the same company. Im no fool and I didn't believe it but for the sake of making our family work I let it go. We eventually moved out of the apartment we were at and took on a bigger more expensive apartment. I thought that we were happy together and starting to build a happily ever after scenario. That lasted for 2 months before the problems came back. This time it was different but no less suspicious. She ran into an old friend of her mother's and started reconnecting with her and her family. I had no problem with that at all until thinga got progressively weird. We only had one vehicle at the time so she would have to drop me off and pick me up from work. Well now that she reconnected with this old friend she started picking me up from work later and later. I would sometimes end up waiting on her to pick me up for 2 hours or more when I had called or texted her when I was getting out an hour before I was done to give her time to be ready. There was an excuse every time for it. The worst of it was when she would tell me she was going to hang out there and that she wouldnt be long. Her version of not long and mine differ substantially because her definition was 3-5 hours when mine was an hour or 2. Finally the situation came to a head when I got the same old story I wont be gone long turned into her being gone for almost 2 days and me not being able to reach her. When she finally called and told me that she was gone that long because she was desperately trying to find her long lost friend's son a place to go because he couldnt stay there anymore and he was basically homeless, i lost it and let her know that I didn't believe a word she said. We argued when she got home but eventually worked things out. Again didn't last long because now we were struggling to survive. She had quit her job and me being the only income wasnt enough. Soon we had no electricity, no heat, barely any food and we were heading into winter. Thats when she decided her and her daughter were going to live with her cousin in the trailer park close by until we could figure out how to fix our finances. Not long after that I started battling with depression like ive never felt before. I had no will to fight for anything anymore. To top it off we ended up breaking up but still communicating regularly until we hit a point where the conversation started getting nasty. All of her and her daughter's belongings were still with me so i told her to come pack it all up and take it where shes staying since she's not living here. Weeks went by and she had only came and got some clothes and a few other non essential belongings of hers. After a month I called my landlord and explained my situation and gor permission to change my locks. Well me being frustrated while changing my deadbolt to the backdoor, I forgot the key in the lock and didn't realize my mistake. I still didnt realize until one night I fell asleep on the couch in the living room after a few beers. I was woken up by her screaming at me to wake up standing upfront of me in my living room which was supposed to be inaccessible to her. She found the key I forgot. We argued and escalated until she blew up amd punched me in the face a couple times at which point I picked her up and forcefully removed her from my house. The whole ordeal escalated to a point that I had to call the police to bring an end to it. After that we had no contact for a while and I was getting over it. I was informed that she had picked up a crystal meth addiction and was throwing her life away. I started to feel bad but I still kept myself from contacting her. It wasn't until I went and hung out with some friends of ours that started dating shortly after we did that I realized I still missed her and cared about her. I went to the trailer park where she was staying that night and was surprised to see that her friend's son was staying there with her when she had said there was nobody else there besides her cousin for months. Even being incredibly mad at that fact I talked to her and we reconnected. She ended up moving back in with me which brings us to the present moment. Now I share her addiction and have no job or relationship with my family so I'm pretty much isolated except for being with her. It wasnt so bad I was depressed but nothing I couldn't handle. Then a couple weeks ago she started acting sketchy like she did before. At first I brushed it off but it got worse. My truck is our only vehicle and she would use it to go to her part time job or pick up her daughter. The issue was that literally every time she went anywhere she would be gone for at least 4-5 hours when she would say she'll be right back. The same excuses kept getting thrown around. I kept hearing her on the phone with somebody whenever I was busy in another room. Then she started only taking certain phone calls in the bathroom or outside again. After a while it bothered me enough that I confronted her about it in which her response was "I'm not doing that you're just being paranoid". I accepted that possibility at first until it kept happening only she was actively putting in more effort to hide certain things that she was doing. She put extra security and privacy settings on her phone. Always kept it on silent and would never answer a call next to me anymore. One day last week she slipped and left her daughter's tablet signed into her Facebook sitting on our bed while she took my truck to pick up her daughter and run a couple errands. After a couple hours my curiosity got the better of me and I checked to see who she was talking to. Turns out she's been talking to, sending naked pictures and videos, and proclaiming her love forever to the guy she cheated with the first time. We have worked through it and she claims it was only a mistake that she going to make it better but her behavior is time I ask her about anything she gets defensive immediately and denies everything and calls me paranoid. She has me convinced now that half of what I'm seeing and hearing are just hallucinations and I'm crazy not trusting her. And thus my decent into madness progresses. I'm sorry for the long rant but it feels good to let it out