You're telling a very one-sided tale. You've also talked about your other issues
before, most of which are not things that 18-21 year old girls are equipped to handle or counsel you on, especially if you've cut yourself off from them so much that they barely know you. I suggest you stop trashing your sorority. It will not empower you in the least. The counselor that you're seeing should have the brains to tell you that. If not, get a new one.
Honestly, even if you were free to join another group when you transferred, I would advise you against it. It sounds like your fiance sucks up half of your non-school time and the various unfortunate things that you're dealing with suck up the other half.