I agree with PP, your body will wake you if it's a problem. But if you're still worried you can prop a pillow behind your back that way if you roll you can't get flat on your back. 😊
Idk if it's worse or not but I always woke up laying on my belly haha my baby came out alright... I don't think it's a huge deal how you sleep unless you have symptoms or complication. I got pre eclampsia at the end so they said I HAD to lay o. My left side... I just propped my pillows behind me or had my boyfriend cuddle me so I would roll over
It's fine. Your body will tell you if it's in danger. I wouldn't purposely lay on your back for a long period of time, but waking up like that there isn't a huge issue