I think it was stress. I have been on this diet for months, 20:4. That is fasting 20 hours during the day, and eating at night/evning in a 4 hour window. I think I need to calibrate my diet. My stomach became like a balloon today, due to slow bowel movements.
Probably stress related. To much fibers in your diet can also slow down your stomach. I have removed most of dairy, and have removed all bread from my diet, I feel good except for this balloon stomach now. It's getting better.