Ok, all of these other issues seem to indicate something may be more seriously wrong. In your first post, your daughter sounded like many other teenage girls- maybe sort of bratty, but honestly, not that bad. In this post you seem to be saying that she might have an eating disorder, is having trouble at school, maybe drinking and smoking,,, or maybe NONE of these things and just trying to get your attention.
I may be reading this wrongly, but YOU seem to be very upset and angry and feel that you are giving her attention and it isn't helping. If your daughter is trying to purposely push your buttons, she is succeeding, because you appear to be totally buying into the drama.
if that is the case, it sounds to me like you need to get some outside help. Your communication skills - for whatever reason- are not working here. It may be partly because of your attitude or approach and partly because of your daughter, but either way you BOTH need to fix it.
I would suggest starting family counseling with your daughter. Just having a third party who is used to dealing with these kind of family dynamics ALL THE TIME will be helpful to you. Sometimes, especially with teens, emotions can run very high. Having a calm mediator, who is emotionally NOT involved in the issues can make a big difference.
Please go start seeing a family counselor with your daughter before things really break down. It doesn't sound to me like she is a bad kid or you are a bad mom- but what you are currently doing isn't working! Try getting some outside help and I bet you will both learn to understand each other better and not get so upset. Good luck!