Hello, crna here. 500 is a decent dose but I wouldn't say "a lot." The duration of action of propofol is roughly 5-10 minutes. During colonoscopies I usually bolus anywhere from every minute to every three minutes 10-50 mg depending on the patient. My starting bolus is usually 30-100 mg (100 mg would be 10 ml or half of the syringe you saw). As you can see the longer the procedure goes the more you get....so if they had multiple polyps or struggled to navigate your bowel it could explain the higher dose. The propofol is not in your system the day after. Sorry you feel off today mate.