Where do the thoughts go?

I had forgotten how much of a toll a long daily commute can take on a person. Having spent the last 3 days trekking up to 57th and 11th, I am amazed at the absolute paucity of thoughts now floating around in my head. There's nothing up there. Just blank, empty space. All I can think is "I want sleep" or, alternately, "I want beer". If I could manage a compound thought, it would clearly be "I want to drink beer, and then go to sleep", but that seems like too many distinct things to keep logically connected in the frayed recesses of my brain.

It's obvious that my commuting chops are not what they once were. If I were to have to do this on a regular, daily basis, I wonder how things - music, relationships, parenting - would suffer? It's just so draining. I'm left with nothing to offer anyone. Makes me appreciative of the fact that it was simply a 3 day diversion from my normal routine.