First, congratulations!
Second, without knowing your relationship, it's hard to say whether this is a natural "we're growing apart and I really can't stand you" or a "I'm pregnant and can't stand you" kinda thing.
Sure, it's totally possible to for your anger to be heightened by the pregnancy. I'm very easily annoyed anyway, but when I'm pregnant, I'm brutal. I can't stand men, as a whole, when I'm pregnant. They just annoy the piss out of me and I know that about myself, so I have to make an effort not to overreact to everything.
However, I don't think your just going to start hating him out of nowhere. There's probably some stuff going on in your relationship that you're unhappy about and need to reevaluate, as it's probably causing some of the animosity you're feeling toward him.