I seem to remember with DS that movement earlier on was initially a bit sporadic. However if you have been feeling it every day I can see why you'd feel worried. Your MW will not mind if you ring her, that's would I'd do.
I was like this; first flutters at 14ish weeks, building steadily and i was feeling something at least a couple of times a day and then nothing for three or four days. MW found heartbeat OK and said not to worry as movement is very sporadic at this stage, especially as baby is small enought to be free floating. Also, if your placenta is to the front it can cushion any movements until the baby is much bigger and stronger.
I would call the MW if i were you just for some reassurance, but I'm pretty sure everything will be just fine
I started to feel my baby move at 17.5 weeks, felt is everyday until about 10 days later and it went quiet. 3 days i worried about it and rang the out of hrs midwife who urged me to see someone the next day. I cldnt wait and DP took me to hospital. They found the heartbeat and explained that if you're feeling tired or a bit low, baby stops moving in order to conserve your energy. Have you been feeling under the weather lately? It took a couple more days and he/she started up again. Am now almost 23 weeks and its going well! For the reasurance, i wld see your doc/midwife but from experience, it can happen.