Doctors usually say that you should be feeling at least 10 kicks within 2 hours. The baby might be in a position where you aren't able to feel him/her move also, so don't worry too much unless you have gone hours or days without feeling movement. Good luck!
When I start panicking about not feeling him I drink a big glass of ice water. That usually wakes him right up lol! I agree though if its more than a day or so call the doctor. I'm 21 weeks
I am 23 weeks with my first and there's some days that I feel him tons other days I hardly feel him at all. The baby still has a ton of room to move around and is very small. Doctors don't recommend counting movements until at least 28 weeks so I wouldn't worry at all !