some friendship problems?

ok, so my friend is a bit of a bully. She bullys me because she thinks it's really fun. But according to her, she is just joking. But to me it hurts a lot.
So one day, I said I would talk to the teacher about it. She got really angry and she starts to talk about me with my other friends. I don't know what she said, but all my others friends agree with her and they start to exclude me. I was so upset because I have never felt that lonely. I couldn't help but cry.
Then after, I went and talk to her, she said that all I said was bullshit and she was 'not nice' to me because I hide stuff from her, I tell my other friend stuff but I didn't tell her. Unfortunately, that other friend of mine was not trustworthy, she told everyone my secret. I was really upset, I felt betrayed.
I didn't know what to do, but then she came up to me and said that we should solve this. We apologized and everything seems fine all of a sudden.
But that night, she send me a message. She said that she will still hang out with me but she is not my friend anymore, she said that the others in the group hate me, and I ruined everything it was all my fault.
She treats me differently from that day onward, but the others seems just like before.
But I can't help thinking they all talk about me when I'm not there, and they secretly hate me.
Is what I did wrong?
Also, one of my friend is going to have a party at her house. but because I can't go, she changed the place for me. But because of that, one of the girl is not able to go now. I'm sure they will be angry at me, what should I do?