UC challlllenger,
Low carb is different than wheat free or gluten free. Maybe that's why rice agrees with you but regular wheat bread does not.
Everyone is so different - some can't tolerate wheat, gluten, or carbs all together - it depends on your system. I can tell you that in general, many UCers have been helped by SCD diet - specific carbohydrate diet.
I know that I cannot tolerate dairy, wheat, gluten.
My advise is for you to start a food journal and see what correlations arise, no?