That really hurts when friends do things like that. Unfortunately, people change as we grow, and it's not always for the best. My best friend completely changed on me around the time I was getting married, and it got so bad I ended up having to ask her to step down as my maid of honor in my wedding
It was one of the hardest things I've had to do, but it was the best decision I've made-so much more came out of the woodwork after I asked her to step out. It was painful, but I realized there was much more to her anger and bitterness, and it was just a matter of time before that ugly side came out to get me.
Hang in there, and surround yourself with people who care for you, and try meeting new friends who have common interests. You may just meet some interesting people!