I sort of cheated when I had to do the prep work last month for my endo/colonoscopy. Instead of starting it late in the day like they said, I began first thing in the morning, about 7:00am. I was in the ladies room all day, up until 7:00pm that night, and then I slept like a baby all night long! I am not telling you to go off your doc's orders, follow them, but I called my GI specialist, asked if I could begin earlier in the day (I need my sleep due to some health issues) and she said that was fine, but to take all of the prep gunk. So, I got to weave off the times I took the prep, just not the dosage or instructions.
In Canada, we have a baby bum cream that is heavenly for diaper rash. By the time hubby got home later that afternoon of prepping, I was bawling like baby, could not even walk due to my tender tushy, so off he went to get some Penaten and within seconds I was fine. Wish I knew this beforehand!
Good luck! The prep work sucked, but the procedures were nothing!