31 weeks

So I am officially 31 weeks as of yesterday however I'm not sure if this is normal or something I should be worried about but the last 2 days I've had diarrhea all day . I see my dr on Wednesday but just want to know if anyone has had this . I don't think I've eaten anything that would make my tummy upset .  Any advice would be greatly appreciated 
Also on a side note does your baby not move as much ? I feel him just not as much as I used to and he moves mainly at night