To say I understand is an understatement!
To say I have walked this very similiar path with my own daughter and using the tough love approach was the hardest, but in the end she thought that by becoming sexually active she was an adult. Yeah! NO!
What I did was try and make up for the lack of stuff in my life with my daughter.
I wanted to be her friend so when she talked back or got smart it was because she was treating me like a friend. I finally had enough and asked her "Do you really talk to your friends that way?" her reply was "Yes" She received a prompt "I am NOT your friend a I am your mom!" That seemed to be a BIG AHA! moment. My house, my car, my food, my gas, my rules you can't follow them you need to take your adult thinking self and do just that. Be an adult! Move out! She did. It killed me.
I know it hurts, I know it hurts to read the stuff she is posting on FB. What others are telling you is true, she needs to fall flat on her bum. You really aren't alone if you want to talk in a pm I am here.