Extreme anxiety in dog because of pregnancy

Start of I strongly dislike dogs always have. But my SO had one when I met him and I accepted it. Now that baby is getting closer to coming the dog has such bad anxiety it's insane. Hes eating non edible stuff in front of us. Whining whenever I am around until his dad comes home and now somehow he got ahold of something that upset his stomach and had explosive diarrhea all over the living room. Hes always gone to the kitchen floor for anything like that if he has a seizure or sudden diarrhea when we arnt home. Feeding him, taking him out nothing has worked so far. I may strongly dislike him but it was my SO's fur baby sense day one and he just wants to take him out back and go old yeller on him now because of frustration calming him down is slowly not working. How in the world can I help his anxiety because of baby. Still got more than a month left till I'm due.