There are times in life when joy is elusive. Note I said, joy, not happiness. Happiness is ever fleeting and, at least in my mind, not worth the pursuit. After all, we are called to be faithful, not happy. We are called to be obedient, not happy. But it is in obedience and faithfulness we will find true joy. So, when we find ourselves less than joyful, we should first check our obedience and faithfulness.
Put another way, we should determine where we have our focus. Joy should be inherent in the life of a disciple. Jesus, the source of all joy, lives within us. The closer we draw to Christ, the more joy we will have.