11 week old sleeping on his back

Li

Hi ladies!

My 11 week old son was just at the pediatrician and they noticed his head is getting flat in the back. They recommended basically keeping him off his head most of the day. So when at daycare and at home (when he can be watched) to nap on his belly. He loves it! And since starting naps on his belly, he has been sleeping at night not well. Before this change, he was sleeping 5-6 hours a night no problem. And now he sleeps about 4, goes back down, sleeps for like 45 mins and then wakes himself up. We get him back to sleep but as soon as we set him down, he wakes up. He is super sleepy though; he can barely keep his eyes open. I’m worried he’s not getting adequate sleep. We were thinking about having him sleep on his belly at night. Side note: he can support his head for the most part, but can’t roll over yet. Have any other moms have their babies sleep on their bellies? If so, how did it go?

I’m hoping no Mom shaming! And thanks!