What could I be sick with?

No matter what I eat, I always get nauseous afterwards and usually throw up at least twice a day. I'm also always tired and have huge bags under my eyes. I've been getting headaches as well. Sometimes I get irritable, but what girl doesn't? I'm also pale and have been told by people that I don't "look healthy." Any suggestions? I've gone to a doctor and they've done a scope, biopsies and they had me eat radioactive food and watched me digest it. They couldn't find anything. They've also done blood test and haven't found anything. I don't know if anyone has had anything something like this before...