It sounds like you are doing all the right things. Your big sis, the new member education chair- those are the right people to talk to. You can also talk to the VP Standards (or equivalent who handles sisterhood & disciplinary issues).
Hang in there- you can't get along with everyone, and while that's easy to accept in theory it's much harder in reality. And you never know what could happen. There was one girl in my pledge class that I really didn't get along with. I never really knew why- we just didn't click. Fast forward to senior year. We went through a fairly stressful experience together and became very good friends. I even drove three hours to her baby shower earlier this year
I'm not saying this will happen with you- but surprises come around every corner!
Best of luck to you. I really do empathize and I hope you are able to enjoy all the good your sorority has to offer.