Hi P,
I'd suggest posting here for support and sharing and then start preparing to change your social group.
It is a big step, but it can be done. I made some changes a couple of years ago, when I moved just 10 miles from one town to another. I joined a few clubs and stuff (music and writing) and I now have a nice new group of 3d friends.
IMHO there are a couple of things to watch.
1. Avoid anyone with 'side'. This is an English term for a person who is sneaky or manipulative. These people are often over friendly at first, or the first one's to talk to us in a group. Take it slowly!
2. Don't get trapped with an outsider in a group. Sometimes an outsider will approach us and try to sideline us in the group. Again, I would suggest taking it slow at first and talking to everyone equally.
3. Wait for things to develop, it's OK to sit on your own for a while, no body ever died from it!
4. This is the big one. Don't 'cross the streams'. By this I mean don't introduce new people to the old group that you were having trouble with. A fresh start is exactly that - fresh.
I guess my last thought is that one straight friend is worth a hundred manipulative acquaintances. If you are straight with the new people you meet, then you will attract straight people in return. It's a good deal.
Good thoughts, M