My friend is being mean?

My brothers ex is a year 8 and my best friend is her best friend and i really wanna be friends with her. The other day she started hanging around us she was talking to me about my brother and we weir really getting along. When i got home i got her email and we started talking to each other she put me in her display name and i pit her in mine and she added me on myspace and i added her as well then she put me in her top friends and i put her in my top friends on myspace. She started be like really nice to m sending me messages and comments on myspace that she loves me commenting my pics on myspace saying im beautiful. She told me she'll bring her camera to school and we'll take pictures together. So when i went to school today she was hanging around during recess and lunch she was hanging around us but she didn't talk to me and she brought her camera but started taking pics with my friends witch is her best friend and could shouldered me i think PLEASE HELP ME!!