It took me about a month to be able to sleep comfortably. It wasn't reflux or nausea, but a weird sensation that my guts were sloshing around. I'm a side sleeper by nature and every time I tried to sleep on my side, it felt like my guts were moving to the opposite side by gravity. It wasn't painful per se, but an uncomfortable pressure/pulling and it was disturbing. I could just envision the cartoon version of my innards lying placidly in a lump on the bottom side of my abdomen. I knew that wasn't true, but it FELT that way. I had to sleep on my back, which was foreign and uncomfortable.
If what you're feeling isn't like I describe, it might very well be some reflux issues. It's common. Talk with your doc about what medications he recommends (you can usually get them over the counter) and follow general reflux protocol: do not eat a large meal within 3 hours of bedtime, avoid acidic or acid-producing foods, sleep with your head elevated.