Decreased movement

Today I've felt baby move but it is way less than usual. He is always wiggling around all day and all night, turning my belly into all sorts of shapes. I've been resting for about 2 hours laying on my side and have had ice water and oj. While I have felt a few movements they are very small and light. Any other time I've felt nervous about his movements the rest and drinks make him go crazy as usual. Should I be concerned that they are less and lighter or is it OK as long as I feel something? I've also had diarrhea on and off for a week and a stomach ache today but no fever and have kept hydrated.