I don't know what to say, i've been trough the similar thing for years, still not knowing what to do in such situations. I remember this one time this girl who had been kinda like your friend to me for about three years and this forth year we were starting the first year in Secondary High School. It was just after the summer. She was asking me how I've been and if I missed 9th grade. I couldn't say a thing all I could get out of my mouth was "no". She hurt me so mutch, the memories still hurts. I wasn't really friends with her but sometimes she were nice and sometimes not and I didn't have anyonelse to talk to or work toghether with in school so what I decidedto do was to go through it. Now I can just laugh at her she had to start the first year two times over again in SHS. She deserves it. It's no use wasting time on people like that. I'm guessing you been trough a lot toghether and have loads of fun memmories and if it's worth fighting for, the do it. But if you feel the other way try to stick to your new friends and go on with your life as it is.
I wish you the best of luck, you deserv better.