Disheartened by boyfriend

It's 12 days before my due date. We have been so supportive of one another over all these months...especially last three. Tonight we had a conversation about my son and for some reason it got him aggregated at me. He shook his head while I was talking and when I asked "why are u shaking ur head" he gave me a dirty look and then said "I didn't shake my head at u"...then he gave me a mean look and just stared at me. It sounds so stupid but when he's like this he just shuts me out. He got up and walked out of the room and hasn't said a word to me since (6 hours). I made dinner for all three of our kids, got them all ready for bed and then said I was going to lay down. He said "ok". We usually spend every night joking around together, watching tv and talking about baby/our days/kids...everything. It's just so disheartening that he's shutting me out and I can go into labor any minute. I'm just waiting for the big move where he sleeps on sofa just to upset me. I'm just sad and don't know how to handle.