When should I worry about baby not moving?

I am currently 25 weeks and over the past few weeks baby has been moving more and more. It’s not always predictable, but I can sort of guarantee it after food, when I go to bed, certain times like that. Yesterday and today I’ve noticed a real reduction in movements - although he is definitely still moving, just noticeably less. Should I be worried about this and call the midwife or is it normal?

Thank you 😊