Our posts crossed over, Brownie. I didn't find D-Mannose irritant to the bladder, but not effective either. That said, I didn't take it for many weeks because it started to cause oral allergy symptoms similar to those I get from tree pollen & when I checked the source, was dismayed to see the brand I'd bought was derived from birch.
I have taken probiotics on & off for decades, but some strains can be irritant because of the histamine generated. Are you taking one specifically marketed for the GU tract?