how do you deal with your best friend getting a new best friend?

[I AM ! ! !]

my best friend claire and i used to hang out all the time.. then 4 months ago this guy she had made friends with on facebook came back home(he was away at college) and she met him and they started hanging out together and she's really been ignoring me ever since.. i haven't hung out with her since but i see her around sometimes and it's always her and her boyfriend or her, her bf and this new guy.. her boyfriend asked me how come i don't hang out with them anymore and i told him and he told me to join them more but i just feel very odd being around her when she's been ignoring me like that.. i'm pretty hurt by what she did and sometimes don't even feel like meeting my other friends cuz i feel they're all the same way.. was ignoring this but now it's making me a lot less social..