I know you’ll be feeling anxious, it’s worrying being recalled, but as others have said the procedure itself is really not as bad as it sounds.
You’ll be given a laxative to take the day before to empty your bowels and colon. So make sure you keep that day free as you won’t be going far from your bathroom.
My advice - eat as little as possible the day before that as the less that goes in, the less there is to come out. It also reduces your hunger pangs for the day of no food. Keep hydrated though and you’ll be fine.