^ That may help, but it's not the only way.
I would not advise water fasting at all. No matter what else, if you are thirsty it is a sign your body needs it. You might be low on electrolytes and then you need those too instead of just water flushing even more of them out but either way, restricting water should only be done on the advice of physician.
I'm still back at my prior suggestion, see a doctor but also try to reduce sodium and increase other minerals. Make all your carbs complex, avoid enriched foods because synthetic vitamins are not the real deal and leave a lot else absent.'
I am not a licensed dietician, but it seems like it would be good to contact one. Not everything needs life long drugs rather than dietary changes, depends on the specifics. I'd always advocate making dietary changes before resorting to drugs, get a baseline from that and then wait a bit, change doesn't happen overnight but gradual improvements don't take that long to notice either, except that a substantial dietary change can take your digestive system a little while to adjust to. If you get diarrhea then keep up your electrolytes but again not too much sodium, measuring your blood pressure would be a good thing to do at this point, and if taking BP meds, consider that interaction.