you can have a quiet happiness that goes on and on, but an exuberant joy thing, that's more intense, but also short lived.
Happiness is how you feel, joy is a jolt you might have then leaves you with happiness...ermmm yeah! Or maybe not.. Ermmmmmm yeah, OK I'm off
Is there even a difference between happiness and sadness? No. "I am" is but an imputation of the totality of existence.