Irregular baby movements

I'm in my 28 weeks. It's said that my baby will move around a lot more, at least every hour. But my baby can goes on a few hours without moving. It got me so scared if something is wrong with my pregnancy. On my previous check up last week, baby heartbeat and growth are well as doctor's saying. Isit normal? For baby not to move for few hours and then actively moves? This is my 1st known pregnancy.