xcrunner,
Yeah just like you and Rob, I've had the same sorta thing happened to me. The solution is simple, but may be extremely difficult to do. Any good friend will understand if you explain to them that you're trying to undergo some changes that will better you. Some will refuse to (even if they say they support it), and they may try to get you to revert back to your old ways, particularly if you were a people pleaser. They'll do this because that is more beneficial to them, and most people hate change. If you are changing your fundamentals and becoming a more social, more confident you, then that will upset the status quo and there is a possibility they will feel threatened by it. This sounds harsh, but you need to rid these types of people from your life. They will only hold you back.
As far as acquaintances go, I'd suggest limiting a lot of your time with them, when possible, until your thought processes are set in stone.
-Doc