Yup, I had this on and off. Often LO would have turned and was kicking into my placenta so wasn't feeling anything.
Have you done a kick chart for the day? 10 movements over 12 hours. One session of kicking and wriggling counts as one movement. One single kick when there is nothing else counts as another. A few kicks in short succession would be another. And so on.
Also try just sitting or lying down and resting your hands on your tummy and concentrate and see if you can feel movement. Drink a fizzy cold drink beforehand might help. Usually gets LO moving.
May well be LO is having a big rest or has changed position so you are not feeling the kicks so much. Also as they start to run out of room around now the kicks etc change and start to become wriggles and squirms. Often you may not notice these if you are moving around and so on. Once you get used to the change in how LO moves as s/he grows bigger you are more able to notice these smaller movements.
Of course, if your kick chart and the cold drink and quiet time don't get results then give your MW a call to discuss. But always worth doing the kick chart and cold drink as often those are the things MW's ask women to do in the first instance.