Lo sleeping on side

FTM and my LO is 5.5 months old. He still fits in his bassinet so when I get lucky I lay him in there. the last 3 weeks we've been doing more cosleeping. Tonight he's been mainly trying to sleep on his side while in the bassinet and when I move him back to his back he goes back to his side. This is stressing me out 🫠 is it ok for him to sleep on his side in the bassinet?