I had one done about 4 years ago. They put me under "twilight sedation." Everyone said that I wouldn't remember the procedure but I remember the whole thing. Even in remembering it there was no point that i was scared. i couldn't feel the tube they put down my throat. It did feel funny for me when they took samples, like i was being pinched (not hard) on the inside. It felt funny. Like others said, make sure to tell them your prior experience (tell your gastro before the day of) so they can prepare anything they need to. Because I was under twilight sedation there was just my gastro and a nurse, no anesthesiologist there. Whatever happened, you will do your best and deal with what is to come. It will be okay.