When living with a person with mental health issues, it's common to obsess about the bad days. Here's a wise idea: Rather than noticing the problems, notice the exceptions. Look for the times when the difficult mood or the problem behavior does not happen.
When is it when your loved one doesn't feel so sad, so depressed, so angry? When is it that your teenager turned in his homework on time? When did your spouse act in a loving way? Sometimes you will find clues to things that will make life easier.
It's also useful to use this approach to help your loved one, even a child, see things with some insight. Conversation starters include: "I need your help. I'm worried about things, and I know that you are not happy either. How would you like things to be? When was the last time they were like that? What did I do or you do to make that happen? What can we try for a week?"
Trying something for a week to see if it makes a difference is usually good enough, unless you are dealing the medication that takes time to take hold. Overall, focusing on the behaviors rather than the emotions may make improving things easier.