When I'm watching a nice movie, I feel happy. But when I head out to the house and discover a mess in the kitchen, my happiness may quickly dissolve.
Happiness is based on circumstances. And because circumstances or externals continually change, you don't permanently experience happiness.
Joy is different. It's psyche-deep, soul-deep. Joy comes from an unconditional, abiding sense of inner peace and contentment. In our society and culture, we sort of get too addicted in pursuing happiness. But in truth what we are actually seeking is joy.
Of course, there is nothing wrong with being happy and having good circumstances. But remember, circumstances change. And because they do, happiness is temporary. It fails to truly satisfy.
Perhaps, you're going through very difficult circumstances. Loss of a job. Physical illness. Unfaithful spouse. Family breakdown. Bankruptcy. Abusive parents. Prodigal children. Business shutdown. Whatever it is, there is hope because circumstances change. Times change. As you do what it takes to improve your situation, you can experience pockets of happiness.
In the meantime, while going through trials, you can choose joy. You can have joy in the midst of hard times. Know the secrets of having true, abiding joy whatever your circumstances.