Congratulations to you and am glad to hear Rowan is doing better. It appears you are learning the same lesson I had to about hydration and nutrition on long rides. A couple of years ago I would be absolutely wiped out and staring into space after long rides, but have since upped my fluid intake (electrolyte and carb mix) and always pack along energy bars and a gel or two. What a world of difference when the body has fuel, liquid, and probably in your case additional salt.

Keep up the good work and best wishes for Rowan