I'm in BIG Trouble!!! Please help!?

Ok. I have 3 best friends. Or I did, now I have 2. Anyway, in the beginning of the school year there are these three girls. P.S, me and everybody I am going to say are 12! Ok, so, these girls make out a lot and date guys who do weed and everyone calls them sluts. They're really popular. So, my BFF Gabby was there too. At first, when my two best friends jordan and ashley, asked her to be in our little BFF group, which has been just the 3 of us for 3 years, she did become our BFF! We didn't know that she was a rumor spreading, gossiping, jerk! The three girls that everyone calls a slut well, one day, I don't know why but I said something really mean! I called them the 3 slut muskateers. And I said it and my friends did too, but then we actually got to know them and they turned out to be really nice, even though they do do those things I said! Gabby called jordan's boyfriend fat because he only got 10 seconds on the flex arm hang! But ashley only got 1 second! So, then Ashley was like, well what about someone who only got one second, and Gabbie was really rude about it and was being a ***** to Ashley, so Ashley said leave! Jordan and Ashley weren't her friend anymore because of the things she said! I was mad too, because she gossips a lot, and is really mean to everyone!!! She even screams at her own mom and is really mean and disrespectful to her mom! Anyway, so a couple days later Gabby told everybody that Ashley said these really mean thing about people when Ashley didn't say any of it! Gabby made it up because they are mad at her! And everyone told everyone and now everyone hates Ashley! Even though Ashley really didn't say any of that stuff!!! Now, Gabby hates all of us even though we didn't do anything, and I'm really scared that she is going to tell the three girls i called the three slut muskateers! I don't mean it anymore and I don't listen to gossip anymore, plus I don't gossip anymore! But I called them that 3 almost 4 months ago. But Gabby remembers like everything when it comes to mean stuff! I am 100% sure she still remembers! I'm so scared she'll tell the three girls! I feel so bad and guilty about it and i wish i didn't say such a mean thing! I completely regret it and take it back! I'm so sorry! I don't know what to do. Gabby gossips non stop and she is really mean to everybody. We had figured that out before but we were too scared not to be her friend because we knew she would make stuff up about us and tell everyone that one bad thing we said which we all regret! What do I do, I'm so scared! Anytime she gossiped we would just ignore it, or say Gabby, that's really mean! And I don't want to be equally bad and retaliate! God, I'm so confused! What should i do? I really need advice! And I feel so horrible for Ashley, everybody hates her and she didn't even say any of the stuff Gabby said Ashley said! Why is Gabby such a *****???? HELP! PLEASE! The whole school will hate me, ashley, and jordan because of mostly Gabby's lies, and that one thing we said about those girls! God, Help Me!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!…