Trying to understand what is going on with me - any help?

I'm trying to understand what's wrong with me. I am a husband to an amazing wife and a father to 3 children whom I love more than I ever could've imagined. But I find myself wishing I didn't exist, hoping than this life is a dream. I sometimes even wish I was just alone and had no one. Its tearing me and my family apart. My wife feels that I couldn't care less about them yet it's the complete opposite. I find myself wanting to be alone which hurts my children because when I work I'm not home and when I'm home I'm not really there. I just want it to be normal to feel normal and to be able to show my family how I truly feel.