Baby not moving?

So I woke up at 6:30am to get my son ready for school, it’s his second day of KG. My husband takes him to school on his way to work, but I stay home with our 2 year old until it’s time to pick him up. That’s just what works for us. Anyway, I laid back down after they left because my 2 year old was still sleeping and ended up falling asleep myself. I vividly remember feeling my baby kick so much last night, and this morning! I accidentally fell asleep on my back. Honestly, it was the best sleep I had gotten in a while, and I woke up feeling good. But it’s been a few hours and I haven’t felt the baby move. I’m sorry if this is as stupid question, but can sleeping on my back hurt the baby? It was maybe an hour/1.5 hours before I woke back up. He’s usually crazy in the morning, esp after breakfast.