Post period cravings

Whenever I'm in I'm always super nauseous and I can't really eat and have to force myself to or I won't at all. but the week after I get off I want everything in sight yet when I do eat I feel super sick.  I used to be anorexic so eating is kinda an ordeal for me I guess I wanna be healthy but it's really hard because of this, what should I do, can someone help?