Anecdotal, non-scientific, observation.
If your electrolytes are out of whack, yes, you can feel thirsty despite drinking copious amounts of water.
I used to have problems with electrolyte imbalances, before I started judicious use of supplements during high altitude hiking. I would feel very tired and thirsty, and no matter how much I drank, I would stay thirsty, but pee alot. Then I would realize that the water was going right through me (doh!). A dose of electrolytes, and I would feel better very fast (maybe 10-15 minutes even). Now that I recognize this, I know what to do (and how to prevent it), but for a time, it was puzzling to me.
P.S. In my case, I don't think drinking too much water "caused" my problems, per se. Rather, I think my electrolytes would get depleted through my exertion, sweating, what-have-you, to the point that drinking more water would not help my situation.
