I totally agree with Jan.
I have a relatively flat stomach, not as flat as I would like, certainly not a six pack and since creation of my Stoma, it ofton retracts inward, although I only notice it when changing my colostomy bag, otherwise I never see my Stoma as a bag is permently attached, especially when bathing.
To prevent leaks from around the Stoma, I use a convex appliance landing zone/wafer.
As for cramps, maybe the Imodium and whatever's been eaten earlier may of caused a little too much bulking up.
On one occasions and totally unaware of the consequences, I ate a bag of Dry Roasted Peanuts. I was aware of the possibility of a blockage, so I ensured to chewed the peanuts and chewed some more but peanuts can cause a blockage or slow down movement by bulking up, regardless of how much they've been chewed, I wasn't aware of this at the time. That night and best part of the following day, I endured stomach cramps, for the first time ever.
It may be a little different for yourself as you've had a J pouch reversal.
Like Jan suggests, I would only worry if stomach cramps are apparent and there's no output.
As for getting a good night sleep; from time to time I suffer from the same. Most of the day I'm tired, not to the extent I need to sleep but lacking energy, which has been suggested as being due to disturbed sleep, which to some extent, is probably true.
I've also come to the conclusion it could be dehydration.
I'm tired most of day, yet it tends to lift late afternoon, coincidently when tired, I'm also hungry, so I eat and drink, normally a couple of hours before bed; but when I go to bed, I can't sleep ?
When I do finally fall asleep, I will awake within a couple of hours, sometimes I awake again to change my bag, so by time I do fall into a deep sleep, I have to wake up for the next day.
It's a viscous circle and probably difficult to understand; it's certainly difficult to explain but somewhere in all that, I think it's due to dehydration.