I think this is the hardest part of being pregnant. Your emotions go crazy.
I have 2 babies. I had a hard time distinguishing between real thoughts and irrational ones when I was pregnant. I would get into such a rut thinking the worst of my husband.
When in reality he was the most helpful supportive, loving man.
What you need to try and do is acknowledge your irrational thoughts as irrational. Try to notice what triggers your "crazy" thoughts and let them leave your mind. When you get over tired, and have these weird emotions going wild its very hard to not be a bi%$ch.
Whenever I had these thoughts I did just that. Instead of acting on them I confronted the fact that they were "crazy" thoughts.
Like I would get mad, jealous etc of my husband going out with his friends.
Now my husband goes out, maybe 2 times a year. I would find myself getting jealous and pissed at him. Then I realized that There is not point in doing that. There is nothing wrong with him going out. Just because I can't isn't his fault, and it's not ok to lash out on him about it.
WHen he asked if I cared, I would say
"honestly, I'm pissed off, but not for any rational reasons. Go and have a blast!"
Its hard, it really is. But if you act on every "crazy" thought you have your marriage will be damaged.
That's when your friends, or family really are a big help. Instead of lashing out, tell you husband the "crazy" way you are feeling. Don't argue, just communicate it to him. He doesn't know what is going on unless you talk about it.