So Thirsty , not diabetic helpppppp

i have had this issue for about 6 months now and have seen so many doctors I drink around 3 litres of water and am still thirsty. my tongue is always white and my ears are constantly ringing. I have depression however am not taking any medication for it. i have been tested for diabetes and also diabetes insipidus , lupus, sjorgens syndrome , electrolytes and everything is clear.. This thirst is driving me insane and is affecting my daily life The doctors are saying they do not know what is causing this i am in desperate need of help😭😭

Have you had a glucose tolerance test? It lasts a couple of hours. Although you may not have diabetes, you could still be glucose intolerant. I am glucose intolerant and I get very thirsty.
Are you taking any medication at all? certain meds can cause you to be very thirsty.
Have you had your liver and kidney function tested?

Thank you for your response
No I have never had the glucose tolerance test and will look in to this urgently.

kidney liver and thyroid have all been tested and ruled out

I am not on any medications…

I have done a Fasting Glucose test us that the same thing?