E.S.
I know you've already gotten plenty of advice, but had to add my own. I'm also pregnant with my second and also irritable this time around. Was never at all with the first. Same way, itgot better for awhile on its own. For me, stress is a huge factor. Only thing, I don't realize I'm stressed until I'm biting someone's head off. I've been focusing only on the things that are most important, and leaving the rest. I don't even think about anything or anyone that might bother me. That way, if I'm not thinking about it/them, I won't be stressed when it doesn't work out the way I think it should and then I'm not irritated. When I start feeling irritated anyway, I just walk away from the situation and let it be, whatever it is.