Is she realy my bestfriend??

I have a bestfriend right, and I always see her in the hallway, but shes with her new friend that speaks gibberish and my "bestfriend" speaks it too. Any way when i see her and know for sure she sees me she dosen't even say wup or hi or anything at all. She use to sit next to me at lunch now she sits with the girl who speaks giberish at a WHOLE nother different table. But we used to be that tight if you saw me u would see her but now if u see her u would see that gibberish girl. But now i was anxious about this whole situation so i called her but she had to go so i asked her real fast why wasnt you talking to me today and she said she was and i said oh yeah!! what just hi then seeya lata so i said any way i see you al the time but u never even say hi then she claims she dosen't even see me when im like 1 foot away from her is this girl my bestfriend after all what is happening??