I never pass by questions about fetal movement, because (and I don't want to scare you, but feel I need to at least mention the possibility) my first son wasn't moving at 36.5 weeks and it turned out he was strangling to death in his umbilical cord.
Call your OB right away and mention your concern. S/he will let you know how to monitor the movements and whether or not you should be concerned. You will likely be told to go drink some juice, or eat something sugary and go lie down in your room, on your side, and count the kicks.
When I tried to monitor this way I didn't feel a single kick. They had me immediately come in to labor and delivery and put me on the monitors and did an u/s but there was no movement at all and ended up doing an emergency C-section which saved his life.
Most likely your baby has just run out of space and is just gonna chill for the remainder of your pregnancy, but because of my experience I always advocate that when in doubt, call your OB.
Best wishes to you and your baby!