Bulimia / annorexia

Dear people on this forum and for all of those who are reading, i have drove myself to depression for my girlfriend because she is always sad or down because she feels that she is overweight or chubby. she is 5'7" and about 110 pounds, every time she eats food (now its to the point of drinking water) she goes and hides or goes to the bathroom to throw up. she is always saying that there is a part of her that is telling her to starve herself to be pretty or throw it up so you wont gain the weight. i have tried to make her tell herself that she is skinny and beautiful but she just gets even more depressed. it has gotten to the point of where her throat is bleading and she is always feeling bad because of her stomach. i have tried to have her get help but she refuses and i feel like there is something that i could do to help her but i dont know what