Keep trash bags in your truck. I ate some bad food once and got sick. It hit me while I was stuck in traffic on the dan ryan in chicago. There was no where to pull over. So I grabbed a trashbag and puked in it while driving in rush hour chicago traffic. Once I made it through chicago and onto the indiana toll road I hit the first oasis and got some medicine and went to bed. Got up early the next day and went on down the road. Good luck.
Reminds me of the time when my parents and I would travel to Mexico by car 15 years ago when I was 7 years old. The trip would be 4 total days and 3 nights of driving nonstop. I had to poop really bad, but there was no rest stops for miles. I guess I was too afraid to poop on the side of the road so I grabbed a trash bag, and let it rip. Ah, the memories.