What to do about my obsessive mentally ill "friend"?

Ok my friend (or so i thought we were friends) is being a *****. She is ruining me and my only other friend's lifes.�Let me see where it started. It was five of us. One of them was a "les" and fell for me and so she couldnt take it and just left. Now this week, my friend "Alex" embarred "Courtney" infront of the guy she likes. She made a huge dramatic show infront of everyone. So "Francis", "Georgia" and I went to comfort her because were all close but she turned everything into a huge drama. Its apperantly all our fault now when in truth we hadn't opended our mouths or barely even payed attention to what was going on. She turned everyone in the school against us because she is one of the popular girls and because her mom works in the school. We've been stared at, glared at, and even recieved hate messages because she has told everyone lies and rumors that she has spread about us. She has gotten back at Georgia by turning everyone against her and shes even threatening her. For me, she is flirting with the guy I really like. She has been telling him lies and hitting on him because she knows I have or HAD a chance with him and she was jeleous because she couldn't get the guy she likes. I find her mentally sick and obbsessive. Its a load of drama,especially for people like Georgia Francis and me because we hate drama and are "chill" people who avoid this as much as possible and yet we were all tied down to this s***. But we're not even in high school. Yea, we're in 8 grade. Too much crap for us. I just feel like leaving already to escape this and become a loner because right now, I dont feel like I'll trust anyone ever again my life so I'll just become a loner. But what hurts me is that after spring break i was going to ask the guy I like to this little "prom" thing and she might ruin everything I worked for with him.�Questions: What do you think of everything? What do I do to fix everything? What about the guy I like? What do me and my onlyfriends do? Thanks!<3