I think the party line on water now is exactly what you have done today, 3 litres that can include what you use to make your packs up, I also include decaf coffee,peppermint tea anything decaffeinated I think can also go towards that three litres.
They do say try and think of your body as a waterwheel , so don't be gulping it down in massive swigs, sipping it throughout the day to keep the wheel moving ....it's does get easier.
As well most of us in our day to day , don't drink enough water so when we have to count what we are drinking it seems like a large amount, after a bit you will get used to it and have true hunger feelings not thirst masquerading as hunger.
I think the panic can come from when people try to down wayyy too much water in too short of a time, that is not good for us and can cause health problems.