Don't worry though a few days later I was fine.
Anyway, the longest road trip I've driven is the annual trip I take to Alabama to visit relatives. This usually takes about ten hours, including a stop for lunch and the odd bathroom stop. Not nearly the kind of hours some people here have put in, I'm sure, but I'd probably get there in nine hours or less if Georgia traffic wasn't terrible. I think Georgia interstates are in a perpetual state of construction or refurbishment. Once I get into Tennessee, it's smooth sailing.
Now, I've had worse for airline trips, but that's probably for another topic.
I hadn't planned on driving straight through, I wanted to drive until I got tired but by the time I started getting tired I was only about 5 hours away from home. The last 2 hours were a real challenge but at that point it didn't make sense to to rent a hotel room so close to home so I had my wife stay awake and talk to me...Which you would think would put me to sleep but it didn't :)
Back in July '06 I was on the third day of a solo cross country trip from New York to Seattle. This happened to be the longest driving day of the trip, covering almost 900 miles from Lincoln, NE to Ogden, UT. While driving on the most desolate stretch of I-80 in Wyoming, nature called in the most urgent of ways. I held (clenched) it for miles between exits, many of which had no services. Finally I got off at an exit where there happened to be a small mom and pop gas station. I pulled up only to find out that the restroom was out of order. Desperate and running out of time, I hopped back in the car, drove back towards the on ramp trying to figure out what to do. That's when I spotted a very large rock just off the road between the on and off ramps. With perhaps seconds to spare, I parked the car next to the rock, grabbed a roll of toilet paper (which I fortunately happened to have in the trunk) and squatted down behind the rock, completely hidden from view. I finished my business as quickly as I could, got back in the car and right back onto the interstate. As if that wasn't enough of an adventure I encountered a pretty intense sandstorm later that afternoon. I sometimes think back to that day and laugh about how I left a piece of myself in Wyoming. Thanks to the anonymity of the internet, I can finally share this otherwise embarrassing story.