I'm aware this might sound strange, but how do I hydrate myself? I drink a lot of water but it just passes through. It's not like I feel particularly dry inside, body seems like a blank space i need to specifically tune into. Intravenous saline (NaCl 0,9%) drips have an immediate positive, almost euphoric effect on my mood and cognition, that's why I suspect I'm chronically dehydrated? I also noticed that vitamin C, niacin and alpha-lipolic acid make me saner and more aware of my body. Any comments on that? 

Home-made electrolytes work -- google "Snake Juice", buy some in the drug store or make some yourself with OTC ingridients, you can find details regarding mixing on wikipedia. Combining with vitamin C makes my mind really clear. I also recommend https://biologyofkundalini.com/ -- great resource, a lot to digest though.

Difficulties with regulating water intake could be a sign of several different medical conditions. I would consult a doctor or endocrinologist if possible. 

I agree that consulting a medical professional is warranted. Diabetes and many other conditions might produce the symptoms you describe.