I dont know what to think with my friends..?

i have three "best" friends. they were cool until about a month ago. first there was sweet and shy Sierra. she was cool until we figured out she was sending naked pics of herself to boys she met on myspace. then they was simple but fun Kelsey. She would be my 'therapist". but if i have problems, she doesnt seem to care anymore. now shes more interested with me finding her a boyfriend instead of helping me get through the fact that my boyfriend is badly injured. Last there was Amie. my best friend out of all of them. she seems different too. she gets mad at me but i cant get mad at her back without being a true ***** that she never wants to talk to again. and she got mad because i stopped giving her messages on myspace because my dad is getting the computer fixed (im on my aunts laptop now). i love my friends but they have changed too much within a month! help?