cant handle the bitches anymore!

well I’ve been hanging around with a group of girls for about a year now…but im only close to a couple of the girls…and there are a couple that think they are..IT basically.. and always make the girls in our group (mainly me and maybe one other) feel really small and embarrassed when they make jokes about us or take the micky right in fornt of us..there is a ‘ringleader’..and she is so bitchy towards everyone but especially me..and I cant stand it anymore..I like hanging round with them and I dont want to stop but its really starting to make me feel depressed when I get put down and ignored all the time…im not a shy girl when you get to know me..but I find it hard to talk to the ‘mean girls’ that I hang around with…I dont know what to talk about with them or even how to pluck up the courage or make them laugh! I really dont know what to do I dont want to go on forever like a ‘sheep’! and I definately dont wna stand up to her cause I hate arguments! what should I do to build my confidence and get evryone to stop treating me like a nobody ?! ..I think im too soft..