I've had nightmares too, it started around 33 weeks and lasted for about 3 weeks, I was afraid to even go to bed because the dreams were so realistic.
Every night. All night. It's crazy!
I've had some really vivid nightmares where i slept talked and pushed my hubby away from me and said that i was afraid of him while i was asleep... I don't remember doing that at all and it really upset him:( he's a big guy at 6 foot 5 and so it took him a while to calm down because he doesn't want me to fear him Like that.
but I don't dream nearly as much since in the second and third trimester just because I wake up so often through the night.
It can be common. Everyone is different. I've not had any bad dreams/nightmares. Just dreams that make like no sense what so ever. I had one where my baby (who is not even here yet) kept turning into sandwhiches and spoons, and I was carrying them around like they were my baby. Very weird.