Does one friend seem to be the ring leader in this attitude? Can you figure out where their attitude about you originated from?

I'd definitely tell them this treatment bothers you. If they don't respect your boundaries, they are not real friends.

I have a difficult, life-long friend. I know she always tries to take advantage of me and will try to make me feel bad, using what I confide in her against me. Yet I still stay her friend, just trying to not cross those boundaries and telling her to back off when she starts on me.