Can't stop being b!tchy?

I'm 19 weeks pregnant, and normally I think I'm a fairly agreeable person, but here lately .......not so much. I feel bad because my husband is trying so hard to help me out and be friendly, but it seems like everything I say comes out totally b!tchy! I really don't mean to be this way, but by the time I think about what I'm saying, I've already said it. Does anyone else feel like this?