Am i overreacting? (sorry i left out some stuff)?

um sorry i reposted this but its cause i left out some stuff and just remebered , well me and my best friend are always doing stuff together and she always says im her best friend and ect weve been friends for 8 years now almost 9. but yesterday we hung out at the movies with a bunch of peoplee and she was acting all mean to me and unusual and talking to other people besides me and then today i looked at her myspace and had written in her about me "lizzie is my absolute best fricken friend" and she had originally wrote "jess (me) is my best friend and i couldnt live withoutt herr <333" and she hasnt been talking to me lately and i didnt do anything to upset her or anything but i kinda feel like ignored and stuff anyo of you can help me? also lizzie is her "second best friend" as she always sayss and she knew her since last yearr