Here is more info about how to do a gluten challenge for a celiac disease blood panel, or for an endoscopy: and this recent study recommends 4-6 slices of wheat bread per day:    

Your feelings are completely valid, and I want to commend you for advocating for yourself despite the initial resistance from your doctor. Navigating a new celiac diagnosis can feel overwhelming, especially when you're adjusting to such a big lifestyle change. It’s natural to grieve the loss of your old eating habits and to feel frustrated by the constant label-reading and vigilance required. But please know that you are not alone, and many others have walked this path and come out stronger on the other side. Healing takes time, and while the brain fog, fatigue, and bowel symptoms can be discouraging, they often improve as your body begins to recover. It’s great that you’ve hired a dietitian—that’s a big step in supporting your healing journey and ensuring you’re getting the nutrients your body needs to rebuild. Remember, each small step you take is progress, even if it doesn’t feel like it right now. It’s okay to feel sad and angry, but also try to give yourself credit for your strength in facing this. The fact that you pushed for answers shows how resilient you are. While the road ahead may have challenges, many people find that over time, they feel better than they ever imagined possible once their gut begins to heal. You’ve got this, and the celiac community is here to support you every step of the way. If you have time, this book was published on Celiac.com's and you might find it helpful: Also, this article has some detailed information on how to be 100% gluten-free, so it may be helpful (be sure to also read the comments section.):    

Welcome to the forum, @Whyz! By "half way to being diagnosed" I assume you mean you have had the blood antibody testing done but not the gastroscopy with biopsy. Is this correct? Were the results of your blood work positive for celiac disease?

Three days of no gluten is not likely to have much impact on serum antibody test results. I have more concern over exactly what test or tests were ordered. When you get the results back, please post them including the reference ranges for the tests for negative vs. positive. What country are you in? Do you have much choice in what doctors you see? Sounds like it might be a good idea to seek out another physician who knows what they are doing in this area of disease diagnosis. At any rate, you have the link I shared above outlining the various tests that can be run so that might be a resource you could share with a physician.

I’m only half way to being diagnosed I’ve started eating gluten free food because normal food makes me feel ill. is this ok