Listen to your intuition. Even make a pros and cons list. If the person can't be supportive, you know what you must do.

I don't think you should hang on to someone for fear of being alone. I think this is a case of isolation being the better good.

But, I'm pretty sure you don't have to let everyone go. Cutting one person away doesn't mean you have to rid yourself of all of them. Are there some you could simply distance yourself a little away from? Continue a relationship as an aquaintance?