Anterior placenta

I'm 29 weeks today and I don't feel my baby move really. I was feeling him pretty good up until a couple of weeks ago. I went in at 27 weeks and got him checked because I hadn't felt him for a couple of days and he was fine but I'm 29 now and his movements aren't like they were they are really light now it seems and I don't feel them as often... Is it just because he's getting cramped in there or my placenta is cushioning some of the movements? It worries me! FTM