Should I worry? I was playing with baby by poking my stomach and feeling him move this morning. After lunch hadn't felt him move much so I tried it again and he's not responding. It's been a few hours since I last felt movements. 18 weeks tomorrow.
Baby could just be sleeping or laying more towards your back. @ 18 wks baby has lots of room to move around in there. If you are really worried, drink something sugary and lay down on your left side, the sugar should wake the little one and get baby to move about after about 30-45 min
Also keep in mind baby is still small ... There are a lot of movements that you won't feel ...