Rolling onto belly

My LO recently started rolling onto his belly at night, but everytime he rolls, he wakes up and starts crying, it's been like this since last week. He does it so often that it's hard getting any sleep at night. We tried not rolling him over and letting him sleep on his belly, but he just cries. He had slept on his belly a couple of time. He knows how to roll back onto his back but he doesn't do it often (maybe that's why ? ) Just looking for advice because im one tired mama.