After coming intimately acquainted with a gravel run-out at the bottom of a hill last week, I wish I'd have read this thread earlier. On the other hand I now recall moments from my childhood I had previously forgotten.
No amount of stimulant can overcome 28 hours of playing soldiers, the only thing that helps is a quick break (15 mins min) and a walk around.
If you are that tired, stop. Its not worth the pain.