Now the girl has decided that it is proper to be a total brat

As if my life isn't bad enough, the girl has decided that it is alright to turn into a proper brat. Her escuse for her behavior is that she is a teenager. She doesn't need to do anything I say - no work around the house, no care for herself, like cleaning up after herself, or getting herself something to eat, etc. 
She treats me like total crap and that's okay, because she's a teenager. She screams, swears, calls me names, insults me, and even throws things at me and it's okay, because she's a teenager. Now, she doesn't even need to tell me where she's going after school or what she's doing.
We had a talk this morning which made me think that I had reached her a little, then this after noon she came home late, treated me like utter crap, and now, at 2:35 in the morning, she's at it again.
She's been thrown off the bus for swearing, and I can apparently expect to have her coming home late every day after school. She makes me want to give up completely on her.
I have just about had enough, really. I've been sick for years - proper sick, where I have been in the hospital, having operations and taking months and months to recover, and the entire time having to deal with her treating me as if I did it to her on purpose. I am tired and I hurt all over, and I am may never recover much more than I am now.
She is a horrible person, when she wants to be, and I don't know if that beautiful child inside her is worth the pain she causes me to try to save. I love her but I don't know if I have the strength to pull her out of this when she doesn't want to be pulled out.