My placenta was on the front too, which did cushion the blows a bit so to speak. I didnt feel any movements until after 19weeks, plus they didnt really start getting stronger for a few weeks after that. wasnt sure they were actually kicks at first coz they were light, but then i did eventually. prob just have to wait for bub to get a bit stronger. plus the ob had trouble finding the hb on mine as well because of the placenta, so i told him where the mw normally finds it on the side and he found it too. im sure all is alright, but again if you are anxious about it talk to your midwife, im sure she can relieve any fears.