this is normal. i'm 6 months(24 weeks) and my baby still does this. one thing u can do is buy a instore heart monitor to hear the baby's heart beat(its like $20 at walmart) and this can always assure u that the baby is fine. i have learned thru research that the baby still moves around but we dont always feel every movement or every movement isnt noticeable enough to where we will feel it. so dont worry but if it makes u feel better always call the doctor. its always better to be safe than sorry. but when u get about 6 months you'll sometimes wish they would STOP moving and kicking the shit outta u. lol. i mean u dont hope they die but gettin kicked in my ovaries and bladder is not fun at all!