I have a friend whose been in this situation, and the worst thing about it is that he doesn't understand how vital it is that he removes himself from that circle. If you understand how unhealthy that kind of dynamic is for you and your friends, you'll ditch them. "Close" how, may I ask? If they make you feel like shit, why are they close to you? Do their actions make you trust and appreciate them more, or less?

Best of luck :)