sleep problem 2nd half of night

I'm a white male, 50 years old, in great physical health, 5'10", 150, eat very well.

I have a very rough 2nd half of the night sleep almost every night after I get up to urinate. Sometimes it's hard to fall asleep again, sometimes I cat nap...sleep an hour, wake up, sleep 15 min, wake up, sleep 45 min, wake up. Never feel very rested.

I fall asleep almost immediately which I'm told means I'm sleep deprived. I love power naps and take them especially on the weekends.

Part of the problem is that I wake up around 5:30 or earlier having gas and then eventually I know my body has to have an early a.m. bowl movement. I don't know how to delay this. I think that if I did find a way to delay this, I'd sleep more soundly in the 2nd half of the night.

I eat fresh fruit and cottage cheese for breakfast almost every day, sometimes with Kashi cereal, sometimes with a high fiber cereal.

Lunch is a sandwich, tuna fish, deli, sometimes a hot meal.

Dinner is usually chicken, with red meat 1x or 2x a week, and fish 1x or 2x a week.

I would give my right arm if someone has the answer for a better night's sleep and a way to delay a bowl movement till at least when I'm completely awake.

Thank you kindly.