Bloated tummy one day, deflated or soft tummy the next?

Sue
Hi ladies. 
My little one is now 26 weeks and I noticed something odd after last night. I was feeling rather bloated for the past week or so and had been semi hard tummy last night and had mild diarrhea. When I woke up this morning, my tummy feel strangely deflated, compared to the past week... my little one is still moving, more than usual today but I'm not exactly sure if it's normal to have a softer or deflated tummy... anyone been thru something similar and could advise? (did check if I was leaking amniotic fluid, but so far didn't seem like anything leaking)