The primary distinction between happiness and joy is that one is defined by the external world, whereas the other is an internal experience. According to Dr. Tanmeet Sethi, joy comes from the same well as pain and suffering.
Money, power, and the popular definition of success bring happiness, but not fulfillment and joy. People who had them all still feel unfilled and suffer is an example.
Because of that, when we find ourselves unhappy (as opposed to unfulfilled) about our life, examining our ultimate life goal can be helpful.
When we know who we are and what we are doing here, it helps guide us to find joy. Joy looks and feels very different from happiness, as it has little to do with perception and ego: being right or wrong, rich or poor, competent or incompetent... It’s the quiet resilience that reminds us to always look forward in life.
