Picking my skin and i dont know how to stop, didnt even know this was a disorder...someone help!!

Ok well I thought I was all alone in this and that I was the only one who did this but I guess not...in a way it makes me feel better but not really because I keep wondering whats wrong with me...I have been picking the skin off my fingers and feet ever since I was little...I pick my fingers and feet until they bleed and sometimes it's painful to walk around because they are so raw from me picking them. For years I thought I was the only one, and I hide my secret from everyone because I was always worried about someone looking at me like some kinda freak. Obviously I cant hide it all the time, and I always get the "dannnng, what happend to your feet/fingers", and I always blame it on cutting myself on accident or stepping on something. Now I have a boyfriend, and he is starting to ask questions. He caught me picking at my feet and hands before and I try to hide it from him, but I cant. I've tried to stop but I cant. Whenever I get stressed out or sad or mad, I start picking, and for some strange reason, it makes me feel better. If someone could shed some insight on this, I would really appreciate it!! Rain