First I will say, please ring and get checked out for your peace of mind. Everyone is different, and for some the experience you describe is normal and for others it's not. Best to be on the safe side.
But I can defo relate.
My pattern (currently 35+4) is there is no pattern. Some days I have a really active baby, other days it appears I don't.
However, I go to PAU twice a week for regular monitoring related to previous issues which I won't bore you with. Let's just call my pregnancy 'eventful'. I spend 30-60 mins on a trace, and have found that I can hear all sorts of wriggles and movements of my baby but I just don't feel all of them. So that has made me more relaxed about the fact that sometimes it seems quiet, because I'm reassured twice weekly that I have a really busy baby.
I have an anterior placenta which makes feeling movement less consistent but I do find quite often I can have my hand on my tummy and feel movement from the outside, but not in the inside.
I know I'm lucky I get the extra monitoring and it helps me feel reassured, but even though I know my pattern is there is no pattern, and the midwives know I don't feel all movements, they still always tell me - if movements feels reduced, ring them.
It's easy to worry about things so do use the PAU service to put your mind at ease, and make sure your baby is healthy and happy in there.