Phase. Same thing will happen when they learn to stand in the crib and can't figure out how to get back down!

Totally a phase. They either learn to flip over or learn to love
Sleeping on their belly.

Read touchpoints on how to teach your baby to self soothe.

Does he have plenty of room to move his legs in the sack? He might be flipping back because he can't move his legs...

My kids started sleeping so much better once they could flip.

My kids did this, I don't remember the crying part though. I do remember them getting so much more sleep when they were able to flip themselves onto and off of their stomach. Maybe give it a few nights and see if they figure it out?

Unfortunately a common phase! He will grow out of it. My baby used to do this but stopped after a week or so.

I think it helps not to respond immediately; the baby needs to remember that he's totally capable of doing it. If the screaming goes on a long time, I would go in-- but I wouldn't run in immediately. See if he can work it out.

DS is 5 mos old - after we transitioned out of the swaddle and the Merlin, we put him in a regular sleep sack. He now rolls over in his sleep and wakes up screaming bloody murder.

He can normally flip belly to back and vice versa during the day easily but nighttime is a different story.

Any advice? Is this just a phase?