I didn't talk to my father from the age of 13 to 18. No specific reason, he just didn't understand where I was coming from and I felt we had nothing in common. Of course there wasn't Facebook back then but the phone was surgically implanted in my ear so not really different. Don't take it personally. She is going through a rough time in terms of hormones, finding out who she is, boys probably and all the other things that go along with becoming a woman. It's a hell of a ride and sadly for you young women can be really moody. My advice would be to give her the space she needs, be there when she needs you without making her feel guilty and just loving her. Unless she is getting in to trouble I wouldn't punish her for her behavior. That said you can certainly limit her time on Facebook, though if you haven't done this before it will be a challenge to implement the changes now. Good luck.
Oh, and after I hit 18 my dad and I became best friends. Turns out we had a lot in common.