The first thing I would do is move out. Try to find a low income apartment or move in with roommates. It sounds to me like your mom is a control freak and the relationship is clearly dysfunctional. If you have to move into a woman's shelter. That way you can get away from your mom for a few days and get some food in you.

My relationship with my mother was exactly the same way and moving out was the best thing I ever did. For some reason there are just parents out there who don't want their kids to grow-up and live happy-heathy-normal lives. I live about 100 miles away from my Mom now and sometimes I think even that is too close!

You need to have the space to be you without constant criticism. Best wishes.