I have not not had one, but about 15 years ago, I worked as a medical interpreter for non-English-speaking patients, and in the course of that worked, witnessed colonoscopies, gastroendoscopies, and other such procedures. You will be mildly sedated. Everything will be OK. It is not as nearly as scary as it used to be decades ago. Good luck! And, it was a mild procedure 15 years ago - it could only have become better since.