Should I forgive her? I don't know what to do.?

So my best friend was acting really weird/sad all day and when we ( Me and my friends) asked her what was wrong she would just brush it off and blame it on being tired or some other lame excuse. And then when we asked her again later, she said that it was personal and had to do with family/friends and we were like "What?" because best friends always tell each other everything. And this girl is usually really sweet and nice but lately she's been making snide remarks and even told my sister that she liked hugging this other girl more because she was skinnier and shows off her dancing skills/flexibility to all of us because she knows we can't do it. And then, after she's home and not face to face with us, she tells me over facebook that "We aren't the same girls she knew before and have turned into those girls who think they are overly pretty and popular and try to act cool. And that we ahve been "mean" to her and given her "attitude" (which none of us have done) and that we are just jealous of her new boyfriend because we don't have any." And then like 10 or so minutes after that conversation, she sends me this reaaaally long txt with a sob story talking about how she was just frustrated and didn't mean it and was crying her eyes out. But for some reason he fact that she apologized so early makes me think that she isn't actually sorry, but just doesn't want anyone to be mad at her. And then in school today she ignored me/us and didn't come to the table and when she finally did, my other friends went over to her and gave her hugs and said sorry like WE were the ones who were supposed to feel guilty. And her boyfriend is one of my really close friends and she told him this whole long story about how I ignored her and it was so horrible and she tried to apologize but I just won't accept it. Am I wrong to not think like me friends and just forgive her like that? I mean I know she's my best friend but that doesn't mean she gets to say anything about me whenever. I don't like fighting, but it just seems like forgiving her this time will just make more problems than it will resolve...