Best of luck to you today. Prepping is never a fun thing.
Here's a few tips:
Drink plenty of fluids throughout the day to stay hydrated (even before you begin your prep). I found that apple juice really helped curb my hunger pangs at those moments when my stomach was feeling yucky and I really, REALLY wished I could have had something to eat.
Once you start your prep and things get moving, use non-alcohol wipes to "pat" dry instead of using toilet paper. This prevented me from having that raw, burning feeling. Line a trash can with a plastic bag to dispose of the wipes and then you can just toss the entire bag once your prep is complete.
Find something fun to occupy your time while you're on the john. I took my mini laptop in the bathroom with me - surfed the net, etc. It was a great distraction.
I hope all goes well and good luck with your scope!