Is she cyber bullying me?

Yes, this is cyber bullying(i got mad reading it). The appropriate thing to do in this situation is just to ignore her or even better block her on face book or what ever. Cyber bullies typicly have a self esteem issue's. They also are physicly inferior, as they cannot threaten you with their demeanor. If you want to get back at her(i do not recommend, do this only if she countinues and the teacher does nothing.) Threaten her with you strength in person (e.g. slapping her books down and verbally threaten her.) But yea block her and talk to some one.