HELP!!!!!!

I have my best friend of 11 years and she has completely changed into someone I don’t recognise and I’ve never felt more alone. in the group of forends there was an argument and they bullied a girl out of the group it was 5v1 and I don’t join in bc it’s bullying, I am still friends with the girl they bullied out and bc of that the group has been living hell, i constantly get ignored, they have another group chat without me, they all talk about me, my best friend told me they weren’t gonna sort it out with me and I feel so so alone, some of the stuff they have done to me has been truly horrible and I have honestly felt like ending it, what do i do to make them like me again bc at the minute they all see me as annoying and I want my best friend back , i hope the relationship i had with her hasn’t been damaged too muck :(