freaking out!

This is my third baby, finally a boy, and I'm 35+1, with less movement than usual. Usually he's moving all the time no matter what I'm doing. But today, well yesterday because it's 1:50 am, he slowed down, the day I turned 35 weeks. I'm sitting up in bed right now and has moved a few times but still not like he usually does and now I can "hear/feel" my heart beat in my ears and I am so scared. I know he doesn't have as much room but am I missing signs of him being in distress? I don't want to make a mistake but I don't want to overthink it either 😟