My friend is getting so mean.

She is only mean to me and no one else. It's not fair, she says that i offend her by saying absoloutley nothing and she swears her head off at me for no reason. She never eats and her hair is starting to fall out. I think she might be anorexic, but the other day she said that it's cool being sick, so maybe shes belimic as well, but that doesn't give her the right to go off her head at me. She has me in tears most days because she makes me feel like dirt. She treats me like you would treat an ant. Is there anything i can do?
:(