No friends

I feel like I’m falling back into depression because of this. I have no one at the moment. I am part of a group of three friendship with a girl who was my best friend and we did everything together and then another girl who got closer to us in college and became best friends with us too. About three months ago this girl started being really mean to me and speaking to me like dirt in front of everyone. I still don’t know why she seems to hate me so much. She only talks to our other friend and never even acknowledges me. Anyway these two hang out all the time now and I only see them at school where I can barely talk because I’m scared she will say I’m wrong or yell at me again. I don’t feel like I can move out of this situation but I don’t know if I can live on like this. I’ve always been really introverted and I find it hard to make new friends and impossible to get away from these girls who I’ve had problems with all through high school. I have no idea what to do as all the people I know at school they know as well and are probably closer to because these girls are both extroverts and easily talk to people. I just don’t know when it will end and how to make new friends away from them.