I will answer Jill's specific questions by email as requested. I will make this public description of my my recent dive day.
It was a 2-tank dive within recreational limits--just over 100 feet. With my computers in tech mode set to GFs that would be extremely conservative for a recreational computer, I knew I would probably bump into NDL, even though I would be within NDLs on another setting. I therefore brought a deco bottle with oxygen. On each of the 2 dives, I incurred a whopping 2 minutes of deco, which I did on oxygen. I stayed on oxygen for a minute or two after being cleared to surface, switched to back gas (nitrox), and spent a leisurely 4 minutes at stop depth before reaching the surface.
I figured I had been ultra safe on those dives, which is probably the primary reason I was in denial for so long when the symptoms started to appear hours later.
Dang! That sucks! I hope you're all better now.