HAHAHA! I'm exactly the same way! In fact, my best "vacation" in the past 5 years was when I drove cross country to move from Nevada to Florida over the course of 6-7 days. I had no schedule and no plans so I "just went". It was so relaxing to know that I could stop when I wanted, or not if I didn't. Check out some little Point of Interest, or even take half a day to visit the Grand Canyon. Oh, and I had my dog with me, so I was stopping every couple of hours anyway to stretch our legs, which prevented me from any loooong, rushed, frantic stretches.
By comparison, when I was in my early 20's, I made the drive from Reno to LA multiple times, and would try to better my time each way. It was about a 450 mile trip, and I think my best was to make it with only one stop in about 6.5 hours. So if there's a plan or a time crunch, then just sit down, shut up, and if you have a weak stomach, you may want to cover your eyes!