I've had two endosopies, probably about three or four years apart. The first one was under very light sedation--right after a colonoscopy. Of course it wasn't fun, but really, it doesn't take long, and wasn't a big deal.
In fact, that experience gave me the confidence to do the second one without any sedation. I had an IV in, in case I wanted something mid test, but when the doc offered that option to me, I accepted. There was a great nurse talking me through it. He took biopsies that time, too. It's not for everyone, but I didn't find it all that difficult. And the beauty was there was no recovery time at all. You just get up and go.
I believe there is an advantage to light sedation. You can help the doctor swallow the endoscope, so it doesn't just get pushed down. I never had a sore throat after either procedure.
Don't waste a minute worrying about the test. You'll get there, have it, it'll be over, you'll be on your way. Hey, if you do end up having celiac, it's not fun, but if you can get relief from your discomfort, it'll improve your quality of life. At least you'll have an answer!
Good luck, Freckle!