My so-called "friend" has been giving my phone number out to people without my permission?

That seems like a very difficult scenario. It's hard when you've known someone for that long, no matter how much they've changed or how. But if she's making you unhappy, honestly, the best thing you can do is talk to her. Keep trying to get through to her. Sit her down and have a heart-to-heart and let her know everything you need to. If the problems still remain, then maybe you should reconsider your friendship. I know it's tough, but it may be for the best. I'm sorry that you're going through this, though. I hope it all works out! =]