Stressed to the max....

I'm 16 weeks pregnant with baby boy #2. Our son is almost 5, and he has been such a terror. I'm at my wits end right now, crying almost everynight. He will not listen to a thing. My hubby tries to discipline him, as do I, but he doesn't listen at all! And trying to get him to stay in his own bed/bedroom at night is a struggle and it just won't happen. I feel horrible because I try to stay calm for as long as possible, but then I loose my cool. I can feel my uterus cramping and tightening when I get like this. We had two miscarriages last year so naturally I'm stressed about that happening again with this going on. My son Keeps telling me he hates me or I'm stupid or he wants a new mommy. I don't know what to do ladies... Please help! Advice on how to get him to listen and sleep  in his own room. I hope to have this figured out better before this second baby comes!