Not Celiac, I was tested for it when I was a baby, seems it was well known here in Oz back in the 70's. It took years for the doctors to figure out why I always was sick.
What wasn't well know back then was food allergies and intolerance's (I luckily only have the intolerance's).
Wheat is no problem for me, but I don't eat a lot of it either, as I stick to a predominantly asian diet (Chinese wife).
Oats, Peanuts, Citric acid (particularly orange and mandarin, not so much lime and lemon), soy, and dairy (especially cheese and yogurt) are my no go foods, there are others but these are the most common.
Things are better these days with better labelling, but you always have to read the ingredients labels and ignore the front of the pack. Eliminate all the cereal boxes with oats or peanuts and the list left is very small.
Sticking with the asian diet, I only really have to watch for peanuts, the small amounts of soy sauce I can tolerate, and tofu doesn't seem to bother me, but soy milk is a no no (my reaction to it is weird, skin goes a grey colour and I get very lethargic)
One thing I found when I lived in SE Asian countries was how little processed food or imported food is used, you may find the same in other third world countries, so if wheat is not grown locally then you may find the entire food supply is GF. As a personal example I can eat basically all indian food except the mild dishes where yogurt is used to tame the spices, luckily I like my food spicy
, you will need to check but I thing you will find that apart from Naan bread all indian food may be GF?
I guess do some research on where you are going and what the local diet is, what foods are safe and what are not. It's far easier to find safe foods in the locals diets then trying to stick to a western GF diet. As an added benefit you may find some dishes you really enjoy and can bring back with you.
One last thing, when I was 17 I got Chronic fatigue syndrome, as a side effect of having german measles, chicken pox (for the second time) and glandular fever all in the same 3 week period. Basically my immune system crashed and couldn't recover, it took 9 months of visiting doctors and tests several times a week until a doctor finally told be the good and bad news, he said good news is I know what's wrong you have CFS, bad news is we don't know how to treat it, all we know is typically for an adult it takes 5-7 years to recover (not really what you want to hear in your last year of high school) so with no proposed solution, a friend did some research into CFS and proposed a new diet. It went like this: Spirulina (I chose tablet form as I didn't like the powdered version) was my only source for all vitamins and minerals number of tablets was calculated based on RDI for all vitamins and minerals, then as a supplement to this plain steamed rice for fibre and carbohydrate and filtered water only for drinking, that was my entire diet for 12 months, the benefit of this diet was immediate, I felt well and was back at school within 2 weeks of starting this diet. After 12 months I kept the diet going and gradually added "safe" foods (things I didn't previously have intolerance's to) slowly one at a time (I believe this is now called the challenge and test method).
So you could check if Spirulina is GF I suspect it is, it is a breed of algae, dried. If so Spirulina and Rice both store well, stock up on both. You won't love
this diet, but you won't starve either.
Hope my experience helps you.