5 months old. Is this sleep regression?

My baby is 5 months old. Since 6 weeks old he’s slept through the night. Recently he’s been sleeping 9pm-6am. He’s learned to roll from his back to his stomach and has been napping that way. The pediatrician told me that was ok since he puts himself in that position but to never place him on his stomach myself. Well for the past three nights now I put him in the bassinet on his back, he rolls to his stomach and screams!!!! I roll him back over and over a pacifier that he spits out a million times just to roll back to his stomach an scream more. I’m exhausted and nothing works. All his needs are met, I can hold him an he calms but as soon as he realizes he’s laying down he rolls again just to scream. Is this sleep regression or just him not wanting me to get sleep?