I'm going to be controversial here and say dont worry to much, obviously drink as much water as you possibly can as its good for you and not good to let yourself get deyhdrated, but dont beat yourself up because you've only drank a litre when you should be drinking two !
Like yourselves i really struggled to get fluids in and to be honest its still an issue for me even now, i know i dont drink enough water daily, but i'm not dead yet so cant be doing that bad really.