I did the same thing.
You have to try to make sure you get cleaned out or they will make you do it all again and reschedule the appt.
I was very lucky. I managed to get through most of the ordeal before I got sick. So they didn't retest. But this was for a diagnostic testing not surgery.
If they worry about it, they are happy to give you the Fleet prior to surgery.
Sorry
Good Luck at surgery time