Hey Greg!
I must say that it's a part of life. Pregnant women's hormones are raging 24/7. I'm pregnant now and I go through these stages when I really hate my boyfriend. not necessarily for any reason because he's very supportive, but sometimes I just get angry with him. The thing that you need to do is to just be understanding and be there for her. Let her know that you are there for her even if she doesn't want you to be (but she really does). It's just part of being a woman and being pregnant. Good luck and hang in there