Dear friend,
I can only tell you, you may be in a real mess if you dont get away from that girl as soon as possible. When someone is into medication and its suffering some kind of mental problems like depression, man! they will never know what they want and once you are with them, they will use you as if you were disposable. I dont blame people like that, since its an illness. But you are not engaged to her or anything like that, and from what you tell, it doesnt seem that she is taking you seriously. Its not worth it man. Its like the sea, the deeper you go, the more difficult to get out.