Middle of the night barf session

I normally go to bed between 8-9:30pm and get up between 5-7am, depending on work or weekend. However, about two weeks ago, I started suddenly waking up between 11:30pm-1:30am to throw up everything I’d had for dinner 3-5 days a week. I’m immediately grabbing the bedside trash can and dashing across the hall to the bathroom, because when I puke that violently, I pee as well. I’ve also ended up with diarrhea a couple of times to go with this gross experience. I’m 32 weeks, and have no idea what would cause this.