Paranoid mama

Ever since I was pregnant, I had the whole "babies must sleep on their backs and no other way in order to reduce SIDS risk or suffocation" thing instilled in my mind and now that my son is 4.5 months and already rolling over, he likes to sleep on his side or in this weird twisted position on his tummy and it makes me so nervous!!! I set alarms throughout the night to check on him and roll him back over on his back. Do any other mamas worry about this? Or do y'all just let your babies sleep in whatever position they find comfortable?