growing apart...

everyday i feel as if me and my best friend are growing apart. our friendship isn't what it used to be.. and i don't know what changed. all i can say is that as days go by im starting not to like her, her attitude or her actions towards me and other people. it sickens me how insensitive she is to other peoples feelings. i noticed that whenever i try to talk to her about my problems she just brushes it off & agrees with everything i say just to get me to shut up. but when she has problems im all ears. we barely talk anymore, and when we do it's her needing me to do something for her. i stopped trying to put effort into talking to her sometimes to see if she would notice, and she didn't. im not saying friends should talk everyday to know that they are still friends, but to act like you don't care if your friends with someone or not is completely different. am i out growing her? what should i do?