[Male, 27, 6 foot 6, 285 pounds] My kidneys and electrolytes are fine but every test says I am dehydrated.

For the last two years every time I go to a doctor for any problem they either says it's a synptom of dehydration, or they look at the tests and say that on top of the problem i am dehydrated.

I've gone to multiple doctors, always the same results. They've tested my kidneys, they are fine. They've tested my electrolytes. They are fine. I drink SO MUCH WATER. They have not noticed a single other problem other then dry eye making eyes hurt and Ehlers-Danlos making joints hurt. Only medications I'm on are genteal eye drops and supplements.

Any ideas for what might be going on?