The joy of the YHWH is our strength. While happiness comes from good things that happen to us, the joy of YHWH can be with us in good times and tribulation. Do not lose heart, while there may not be much happening now to make us happy, think of what lies ahead for those that love YHWH. For it is written that Yeshua himself endured the cross and scorning its shame, for the joy set before him of being seated at the right hand of God.
There is a great promise for each of us to consider written in 1 Corinthians 2:9:
However, as it is written: “What no eye has seen, what no ear has heard, and what no human mind has conceived” — the things God has prepared for those who love him
Surely what awaits is greater than we can imagine now. Have faith in his promises. Take heart that while we pass through the darkness, we are in his light and heading closer and closer to being next to him. We are here to be tested, but when we are there, we will have overcome and the joy of YHWH will be great, but we can experience this joy even now, while we pass through the darkness.