Sounds like a 0 calorie flavored water may be what you need. I buy the 1 liter flavored water and then dilute it to make two liters. It is too sweet straight. I have diluted 3:1 but the flavor is not strong enough for me then. It makes it much easier to get the water I need when it is flavored.
Johnie

Johnie has a great idea here. If that's what might work for you, I would also recommend putting a serious dollop of heavy cream in it. That cuts down on the aspartame bite and makes it taste like a smoothie!