Babygirl-I am so sorry that they are behaving so badly! 'They' being your former friends and your sister(I read your post yesterday). It really sucks to have to deal with that. IMHO, they believe they are doing the right thing, making God happy. It doesn't make it any easier for us to deal with but it does help to understand their thinking.
I agree with some of the other posters- act happy, proud, positive, etc.. when you see them. I'm sure it's a little unnerving and hard to compose yourself when you first see them, or at least it was for me, but you have nothing to be ashamed of. They are the ones who are wrong!
There used to be a woman at my hall years ago that would intentionally give me dirty looks and act horrible! I started to sit next to/near her on purpose, just to make her anxious. Eventually, that crap stopped. lol
Take care and be strong!!