Friend issue.?

There are three girls, lily, natalie, and sylvia, who im having big problems with. Two years ago i was very mean and lied to lily and natalie, but last year they said they were over it. Sylvia is best friends with the two of them, but not so much with me. About a month ago I was surprised to here that she talks about me, calling me things like fat and b****y, when I don't even know, or talk to her. My two friends, natalie and lily, have never been the same since my betrayal, and have been pretty mean, like they always talk about me behind my back and stuff. Recently there was a party, and they told the story to everyone and finished it with"and to this day, we are still really mad at her". I was so mad, and its mostly natalie whos mean to me. And also, they told me that they forgave me, and they could've told me the truth. So now, all three of them(lily, natalie, and sylvia) talk about me. We all do a dance cl, and they always make comments on me, that are mean of course.