Insomnia insights:

Happiness is an emotion. It only exists within your own head, and thus there is nothing to pursue.

Put aside happiness, and find a purpose. A purpose exists outside of yourself and can be found. Your purpose is how you fit in with those around you for mutual benefit

Purpose is impersonal and outward looking. Meaning is personal and inward looking. Don't confuse the two.

The reason selfish people are unhappy is because of purposelessness. Find what you were meant to do.