It sounds like she has a lot of personal issues going on and she is taking them out on you. It is also possible that there is something more going on in the relationship that she is dissatisfied with. I would try to sit down and talk to her and let her say how she feels. Let her do the talking and ask her questions. That is the only way you are truly going to understand where the source of the problems are coming from. Maybe she needs to seek professional help or maybe there are some psychological issues that need to be treated. I think better communication is the key issue here and that is something that doesn't seem to be happening.