Katie,

As you are experiencing first hand that teen girls can be mean, snarky, back biting, immature, etc.  Unfortunately I think this is one of those Rites-of-Passage going through the teen and early 20s years.  Those girls and women here have a better and more first hand perspective than me as a middle aged man.

At your age is a time when you really need to develop your own inner resources.  Unfortunately you are at an age where peer pressure, acceptance and influence is at its height in your social development phase of life.

All I can suggest is that you find new friends that you are more comfortable with and who are more accepting.

Mean people suck.

Mark