Donn
That sounds like plenty of water for sure.
You may want to look into the "water cure" as there is a salt factor that is important for proper hydration.
Possibly you are familiar with it.
Believe it or not a person can actually have a dehydrated body if proper salt is lacking even if consuming plenty of water as there could be an imbalance between the water inside the cells and outside of the cells.
If your working out as you describe, you could be losing some salt.
Just some thoughts on the subject.