Hello Lil,
You poor thing. It sounds terrible, and you must really be desperate to resolve this.
It looks like the reason your sister has now become more distant, is because she has perhaps allowed the fight memory to fester. It starts off as a little sore, then gets worse.
Is there know way that you cannot go and discuss all this with her - lay your cards on the table - let her see how distressed you are, and that you desperately want and need to resolve it all?
Families and friends are staying well clear (which is the best thing really), so you do need to tackle the situation on a one to one basis.
Both of you have to listen to what the other one feels about it all, and the only way foreward is by you both meeting up and discussing it.
Hope this helps,
take care and try not to let it eat you up inside,
n00dles xXx