Well, that is a good idea, I think, and might play a little role. I am indeed not doing much exercise at all until my back heals. Though, I stopped exercising over 3 months ago and could easily drink 300-400 milligrams caffeine a day, no problem, despite not doing too much exercise. This issue really only cropped up once I started taking the hydrocodone, recently!
I'm thinking the hydrocodone exasperated some condition, like GERD, and combined with my previous hypoglycemia.