Toxic relationships and depression

My relationship with my girfriend ended about 3 weeks ago. We were together for 4 months but it involves 3 breakups that left me in a terrible mental state. She broke up with me twice and I broke up with her the last time. Over time I realized that she was very manipulative and would play on my emotions but also follow that up with lots of love and intimacy. Over time I believe I formed a trauma bond with her. I wanted to break up with her many times but everytime I tried to leave I became emotionally distressed as well as physically. She had a fear of abandonment and I put up with all of her shit. After I last broke up with her i regretted it and we were working things out but we both made bad decisions and towards the end of the relationship most of it was my fault and I was in a state of pain and anger and I said things that I feel shameful for saying. Through it all we stayed in contact and i got mixed signals from her until she found a new supply and immediately rebounded. It left me wounded but in the end I was talking to a girl sexually and she had my snapchat info and I told the girl I would come over. This was during the breakup and after she told me it was over but she tried to tell me after that she was crying and not moving on and that after that she decided to completely leave me. She has her flaws many of them but for some reason I became codependent on her love due to not receiving proper love as a child. I’m left with mixed emotions and trying to change my perspective but I cannot stop ruminating about what I did wrong etc. I know this person wasn’t right for me but it’s hard to let go and all of the good memories come flooding in and bring me pain. She tried to rub her new relationship in my face in a way because of the other girl but I really did love her well throughout the relationship and I was an asshole towards the end. It’s just hard because I really built an entire future in my head with her. But i’m also left realizing that it was more of an attachment than love. But it still hurts and I feel all alone and when I wake up my anxiety overwhelms me. I have dreams about us reconnecting and everything being okay but I feel like I’m living in my own personally hell hole that I cannot climb out of. I can’t stop obsessing and ruminating no matter what I do. She’s completely uneffected while i’m left traumatized