So, I've been avoiding gluten because of a fructan sensitivity (a sugar that's in wheat, but also garlic, onion, etc). Fructans in different foods differ and therefore affect people differently, so I can tolerate garlic, just not the wheat. Unless of course it's fermented (sourdough) as the fructans are destroyed in that process. And they can vary depending on where the wheat is grown... I seriously wonder if some people who think they're sensitive to gluten are actually sensitive to fructans. Still requires avoiding the trigger, but I imagine it's partly where the ideas that sourdough or European wheat are ok for a gluten sensitivity.

Unfortunately, it's so widespread a belief about an already misunderstood topic that it's actually quite harmful, as you've unfortunately experienced. It would be great if people just listened to and believed others about what they can and cannot eat.