You will drink more water if it tastes good. I’m dead serious. Throw some mint in there, throw some lemon or strawberry or a little flavor packet. Your brain likes things that taste good.
Happiness isn’t a choice, but you can choose little things to help make you feel better. You like having bubble baths? Have one! Does going on a walk make you feel more relaxed? Go out and have a walk! Getting motivation to do things sometimes is hard, but doing tiny things for yourself here and there is a step towards recovery.