What did i do to make my bestfriend hate me?

so latley ive been having trouble with some friends.u see my junior year in highschool i met these 2 girs named kendall an emily they were the populare kids in school always dressed nice and everything and then senior year came and emily started to hangout with this girl named cat..and cat is the schools biggesst snob and a backstabber.now emily acts just her. she gives people dirty looks and is always mean to people. just like cat.me and kendall are still bestfriends..what do i do