You need to know that you may always "feel fat," but that that doesn't mean you are. Get yourself to the library, there are books that will help you understand and overcome your problem.

But you know what? I think you should tell your parents, as they probably suspect already, given how thin you are, and your admitting it to them will be a huge relief to them and you can all move forward together.

Every anorexic I have known thinks her problem is a secret, but everyone around them knew she had a problem.