Its normal try drinking something sweet or cold or lay down on your back or side baby might be sleeping more during the day while you move around that's why you probably don't feel him /her move
I'm pregnant with my second one as well and I didn't feel him till I was like 21 weeks so hopefully by then you'll feel movement !
Pregnant with 2nd child, 33wks and didn't feel her kick or move till almost 30wks.
I didn't even know I was 20wks pregnant at my first ultrasound bahaha
If you don't mind me asking, how did you deliver your first? Sometimes c section mommys can feel movement bc of the numbness of their incision. That aside, every pregnancy is different some women don't feel movement until much later. If your dr isn't worried I wouldn't be