What should I do about this? whats going on?

okay so me and my girlfriend have been going out for a month probably, we were going good the first 3 weeks but randomly this last week she hasnt been answering my facebook or anything or phone calls. shes been updating her status and answering other people but not me for some reason. I havnt done anything to her so I dont know. before we went out her friend asked her why she liked me and she said cause I was nice, and when she asked if she thought I was good looking she said im okay but not good looking. her friend told me this so I dunno maybe she changed her mind and prefers looks over personality. whenever we did hang out shed only kiss me if I started it, and she kinda acted iffy about it when we were, she acted like we were more like friends than dating. I really dont know, what is your opinion about this? before we dated she acted like she was crazy about me and was all over me, but when we started dating she changed.