Should i talk to my friend ?

Amm see im like bestfriends with this girl in my school hu i new for a good while but she gets on my nerves sometimes. Like i asked this fella would he meet her and he said no and i told her that and a few mins later i geard her telling other friends that he said yaa abd she was stunning !! And she added my bet friend on facebook hu she didnt no before and that goes to a different school but she tells her absolutely everything and im with her every day at school !! And also today i was going to a match with her and she kept puttin on fb how much she was lookin forward to it and at the match i went and sat beside her with my friends and she got up and left amd she was avoiding me for the rest if the day :/ she also makes up the biggest bullsh*t like and nowan believes her ! Amm i dont no whether i should talk to her when we go back to school or just ignore her and i actually cant hold grudges against people i just let people wall all over me :/