Hi Poppy,
This is a tough situation and I feel for you having to go through it! I, like Kimberly, was like your daughter once, too - somewhat.
A few suggestions:
1. Try to find out if your daughter is using drugs. That obstinate, belligerent rebellion is often a sign of it. Take her to a doctor for blood work if you have to, but find out. Find out if she's sexually active, too. Peer pressure could be making her feel that she needs to do certain things in order to fit in, and these are certainly not the right choices! If she is having sex, and is feeling pressured about it, you definitely need to know.
2. If you had a good relationship with any of the friends your daughter left behind, consider calling them and picking their brains - maybe they can give you some idea of where your daughter's head is at.
3. Try sitting down with your daughter to just talk. Just you & her. CALMLY. That's huge - you have to keep it together for both your sakes. And try to talk to her woman to woman, not mother to daughter. You may get further with her if you put her on an even level with you. Also, don't put her new "friends" down in any way - it will only push her further away from you. DO MORE LISTENING THAN TALKING. You're trying to get her to open up to you because my guess is that something actually happened in her life to trigger this behavior and you need to find out what that something is - get to the root of the problem so that you can help her resolve it.
The thing that happened to me to trigger this negative behavior is a bit too personal to put out here, but please - feel free to contact me if you'd like to talk about this. Maybe hearing "the other side" will give you different perspective on how to handle the situation.
I wish you all the best with this and I pray that you and your daughter will both come through it just fine.
L.