fake friends 😤

So I’ve had this friend since 7th grade and me and her have always been super close. I’ve always known that she had something kind of off about her because I’ve had several people tell me that she would 1. talk bad about me behind my back or 2. just tell others that she only is friends with me because she wants to be “popular”. I’ve just kind of ignored it because the last time I confronted her about it she exclaimed that she never do that to me and she values our friendship so much. Anyway it’s now junior year of high school and something really bad happened to me just this last summer like something very personal that could really ruin my life if it got out, I told her about it though because you know I trusted her we were best friends. Anyway I had a group of people come up to me at a football game telling me that this girl that I’ve been Best friends with has been going around telling people what had happened to me this summer and she is twisting the story completely to make it sound worse. Not only that but she also spread other rumors around about me and just flat out is trying to make people hate me. I didn’t know how to take it, because I kind of expected her to go around saying that kind of stuff about me to everyone. I know that’s really bad but she talk badly about other friends of hers so much I just kinda knew she was gonna start something about me. The people that told me used to be really close friends with her but they actually stopped being friends with her because she would go around telling personal business about them to others. anyway I don’t know what to do now I confronted her about it after I figured out she’s been going around saying stuff and she still is saying that she never did that and that she loves being my friend and made up a completely weird story about it. I even have screenshots of her pretty much confessing that she did it to other people and I had people who heard the rumor send me a Snapchat saying that they heard it from her. I sent those to her but she still is not confessing. I don’t know what to do I’m not to want to start drama or to pick fights with anybody, but this is something really serious and I it’s been going on for such a long time but it really could just ruined my whole life. Any advice? I can’t tell my mom about it and I don’t want to be completely rude to her but I just don’t know how to handle the situation.