Of the three, only one can be done on purpose today. Happiness comes and goes with the weather and the news. Health keeps its own timetable and does not take requests.
Gratitude is the one with a handle on it. It can be started deliberately, at a bad moment, in a bad week, and it tends to pull the other two some way towards it. That is why it sits last in the list and does most of the work.
You do not have to feel it first. Naming one thing usually comes before the feeling, not after.