Hello everyone. I've started noticing that my (6-month-old) baby start…

Hello everyone. I've started noticing that my (6-month-old) baby starts falling asleep suddenly during the day. He can be playing or talking in the middle of it all and just closes his eyes and falls asleep. This has never happened before, it causes me fear. Has anyone experienced this? Maybe it's nothing, maybe not, but I don't want to run around to the pediatrician.