I have a problem. I'll go 20-48 hours without eating or eating just enough to keep myself functioning. I'll do this for maybe a week to two weeks. Then, I'll eat every day but no matter what I eat, even if it's just plain bread, my stomach gets so upset to where I either throw up or get the runs. Also, about 50% of the time when I do eat, I'll get the sudden urge to vomit and I have to spit out my food or I'll puke and then I can't eat anything else for several hours. What's wrong with me?