It's actually not the procedure, it's the prep, the lack of sleep the night before, and the inability to eat real food for 24+ hours to make sure your colon is clean for the Doctor to see properly with the scope. After I got a good nights sleep and some real food, I felt better. They gave me anesthesia that knocked me out completely until I woke up in the recovery room, the anesthesia's effects can also linger for awhile. I was told not to drive or do complicated tasks until today.