@XiaoMei
I am sorry that you're having these problems with your friends. Some of it might just be to do with them being so young, and quite possibly insecure. But give them some time and it's possible that they will come to feel a little more comfortable, and hence able to deal with your situation.
I had one friend, staight, who behaved like an ass. A few month after that he called me and we sorted out the issue. He felt really bad for what he'd done.
My gay friends have been fantastic, and make an effort to include me. Even my ex-boyfriends (For some time I tried to see whether I might be able to live as a gay man) accept me. I think they see a much more consistent and happy person.
Try to educate them when you get the chance. If they won't listen, honey, move on and find a crowd of people who are happy with the person you are.
Julia