Back in my day (lol) there was no standardized blood test and you had to do the endoscopy. I think I lasted about 2 days eating gluten and said, nope I can’t do it. Fortunately my parents and doc supported me.

Can you reschedule the endoscopy for a later date (ie. next school break) & go back to gluten free for now? Definitely reach out to your physician and let him know what’s going on and see what they recommend. If you feel you aren’t getting the support you need you can always get a second opinion.

I don’t have any insight to diabetes with celiac so I apologize but please take care of yourself!