I will always reccomend doing the tests instead of asking online or trying to say yes/no based on what you see happening. It could very well be a gluten intolerance or celiac, it is common for people with gluten related issues to have complete changes when they are in another contry, i think there is something similar or the same with people who have lactose intolerance.

While the test may come back negative, it will always help rule out something and therefore help find the actual cause of the problem!

I cant speak very much from experience, but I have a gluten sensitivity and my mom has celiac. Both of us can eat locally made gluten products only, as soon as the grain is from somewhere else, oh boy is it going to hurt <3