Everybody has their truth that they have to understand and embody. Happiness is overrated and nobody can stay happy all the time, not even people who have every reason to be.
Instead of being happy and serving others, you should be fulfilled and serve your truth. Truth serves the human race, you serving truth helps others.
A person in possession of truth literally does not care how others treat them. It’s so far beneath them that they barely even notice how others act. It’s like froth on top of the sea, what you care about is the wind and the surf.
Find your truth.