"Endoscopy"

I had an endoscopy procedure done this morning and had a bad experience. I wasn't at all nervous for the procedure as injections don't phase me and I'd specifically asked for sedation so I would be drowsy during the procedure and wouldn't feel a thing. However when entering the endoscopy room I felt very pressured by the staff to opt for throat spray instead of sedation as the staff seemed really reluctant to give me sedation. I was adamant about sedation as I'd heard horror stories about endoscopies which had been done only using throat spray, so the staff said they would sedate me. They said it would take 8-10 seconds for the sedation to kick in but it didn't kick in at all, I was completely awake and could feel the entire thing. I didn't feel drowsy at all. For someone who isn't normally scared of procedures or surgeries this procedure completely changed that for me. After spraying my throat the doctor put the mouth guard in and made me swallow the camera, my gag reflex is extremely bad and I was wretching/ gagging through the entire procedure as it felt like I was being choked. My mouth was full of saliva and which made me feel like I was choking more and the entire thing was the most uncomfortable procedure I've ever had done. I was trying to ask the doctor to remove the tube because it was so uncomfortable but the gagging/ wretching made it impossible to do so- I felt like I was going to vomit everywhere. I was wretching so much during the procedure that I had tears streaming down my face. After being told that by having sedation I would not feel a thing I am extremely reluctant to believe that the staff actually sedated me, or gave me such a minuscule amount that the effect was negligible. The whole process has made me terrified of having another endoscopy or colonoscopy in future. The only positive thing about the experience was that the staff were very polite and understanding.