I was in a very similar situation about a year ago. We had two girls on exec with very negative attitudes who almost ruined Alpha Phi for me. Their negative attitudes permeated the entire chapter. Everyone had a bad attitude about Alpha Phi.
It took some time to realize that I wasn't alone. Many of the sisters felt the same way. So what happened was that I talked to them, and we agreed that things needed to be changed. I came back right during I-Week and told the sisters how upset I was about how I had been treated. I was welcomed back with open arms, sans those few negative girls. But at this point, everyone saw them for what they were, so it didn't matter anyway.
The only advice I can give you is to stand up to your exec if they're wronging you. If they're making you feel like you can't even be your own person, that's wrong. Wear whatever you want (within reason of course... no just wearing your letters and no undies and pants to class
) and be your own person. What are they going to do, bring you up on Standards? If they do, talk to an advisor, and so up the chain. They aren't going to get away with crap like that.
Remember that as a junior, you do have quite a bit of power, as long as you are respected. The newest girls and your next batch of new girls will all look up to you because you're going to be a senior. You are their role model. Be a positive one.