I don't know what to think anymore.....please help?

I don't know what is wrong with me at all. I've been in and out of doctors, and even they can't explain myself to me. I have contiously had this persistent anxiety that creeps up on me, and it just makes me feel like I have no control over myself. I worry so much, I have bitten my fingernails so much that it looks like I don't have any. Everytime I look at myself, I can't help but to cry and feel like a worthless mess. I don't want to be around my family anymore, I don't have anyone to talk to and everyone acts like I am overreating. They all say what happened to that bubbly little girl they used to know back in gradeschool and college. I also have these terrible bouts of rage, where I will just cut and sc at my arms until they bleed, and I will sit and just writhe in my own pain. I've tried smoking cigarettes or drinking excessive amounts of coffee, anything just to distract myself from my pain. It feels like something is practically controlling my mind, and my soul at that.