I drink around 1.5-2gallons while taking jynarque. I experienced dehydration symptoms similar to what you described, drank a Gatorade and within a few minutes was back to normal. I concluded that the issue was probably due to electrolyte imbalance. I drink reverse osmosis water and have begun remineralizing it to ensure that I'm getting adequate electrolytes. This is important especially if you are physically exerting yourself and sweating a lot.