I assumed OP would be willing to say it it was "just" that. This being the Internet and all, people admit to way weirder stuff all the time.
When I was a Boy Scout, we often had kids who would refuse to go. It was a whole thing that we had to check on. (Along with asking everyone how yellow their pee was.)
I remember one guy was in tears on the hike out, and it turned out that he had faked out the scoutmaster by taking a walk with the TP and shovel, but not actually gone. Poor kid was barely able to walk, but kept insisting he couldn't void either.
I only learned later how serious it can get if prolonged.