Not liking this stage

I've just entered the really irritable, easily annoyed, quickly snapping stage of pregnancy. I don't like it. I'm usually a happy, positive and patient person. The last few days my fuse has been very short and I have snapped at most members of my family more than a few times. More than anything I am grateful for a husband who gets that this isn't me. He wants the old me back, but understands that I want this over as much as he does. I'm tired of being pregnant and I'm not even halfway. Who decided humans need nine months gestation?