I hate how my stupid friend is acting!!!?

Ok, so last year i made a best friend in like the last month of school. It was fun, we had lots to talk about, and we just hung out at lunch (just the two of us). this year, I made a friend first, and then introduced them and that was the worst thing I could do because now they talk like hell and maybe sh*t about me!!! how rude!! they leave me out of conversations and are such biters!!! I was like the "daredevil" of our trio and now this b***h is trying to be that!! SHADY!!! rite? anyways, now they TOTALLY leave me out (like when I make a joke, they say "retard!" ) HOW STUPID RIGHT?? and the other one laughs!!! AS***le anyway, they went to movies and sh*T and i feel really bad and depressed. The worst part is we can't talk about it because she tries to act like a "popular" bi*ch even though she SOOO ISN'T one!!! so please tell me what to do, I want to distance myself from them, but they are always together and I feel like I'm just a tool, someone to just be...there. that's all i am to them. please help! is revenge the right way?