I would go all day at work and have 1 glass of water, not feel thirsty. I became quite unwell, to the point where I was having headaches all the time, felt faint and really unwell, zero energy, was having to take naps after work on an afternoon. Had blood tests the lot nothing wrong with me. A friend suggested I wasn't drinking enough fluids, I sounded dehydrated.
Bought myself a 2 ltr water bottle to put on my desk - detest water so on a morning I fill it with 2ltr water and some juice. I make sure i drink it all before I finish my shift. I have another of the same bottle at home and try and drink the same at home, but doesn't matter if i don't finish this one. Anyway, 6 months down the line, no headaches, full of energy, lost weight, no nana naps on an afternoon, never felt better.