What do you do when your friends turn their bak on you?

Oka so me & this girl who used to be my best friend arent talking at all and some of my other friends were mad at her too until a couple of days ago( im mad @ her bc she keeps insulting me & hitting me & talking behind my back ) i have told my old best friend tht i was mad at her & she calld me a b**** & a stupid a** who*e... My other friends think that i caused all the drama and are avoiding me, one of them said bc of what i did 2 my old friend and when i askd her what she said tht my old friend told her tht i cussd her out & made out with her boyfriend... I have never cussd at someone (sometimes when im mad ill cuss under my breath but i have nvr gone up to someone and cuss) and have never even met her boyfriend... What do i do?