Regurgitation of food hours after eating?

I've started taking omeprazole, have been on it for 6 days. So far, so good to be honest. It seems to have reduced most of my IBS symptoms, and I'm not getting serious diarrhea like I used to, which is really nice. The only thing that's taken me by surprise is that I regurgitated some food today.

I had a nice large rice curry dish, and have experienced no feelings of discomfort (other than a headache and sinus stuffing feeling that I attribute to other causes). I laid down just a moment ago and I regurgitated some whole grains of rice.

I was a little shocked because I ate this meal about 4 hours ago. Is it normal for omeprazole to slow down your digestion?