Cause for concern???

FirstTimePregnancy

So this morning I woke up eary and counted 13 movements in an hour during and after breakfast between 6-7am.  Since then, I have noticed that LO has been quite inactive and it's starting to worry me.  I just used the doppler and her heart sounds fine.  DH says I shouldn't worry since she is just sleeping, as long as her heart beat sounds good.  But, being a FTM I cannot help but worry because I am getting very little movement.  I tried eating something and laying on my side, but still cannot get her to move....but have done the doppler since then.  I have heard that babies this far along often sleep more frequently.  Do you ladies think that this is cause for concern?  TIA!