Past the point of exhaustion, but not fully awake...

When I was younger and I had reached the point past exhaustion, I would reach that golden place of being fully awake. But today, when I left work and could not remember what day of the week it was or that I had drove in to work, I became worried.

But it did not end there. When I went to the chiropractor and could not remember how to sign my own name, then I knew I was in real trouble. Is this a sign of getting older or just that I have reached the point where I am just like everyone else in terms of stamina and performance?

I know it sounds sort of arrogane that I am worried I am falling to the level of average humans, but truly, for all my other averageness, I used to have the most insane ability to thrive off stress and lack of rest. But if I am no longer THAT guy, then what guy am I?

(And yes, I love kitten pics, shoot me!)