We also glory in our sufferings, because we know that suffering produces perseverance; perseverance, character; and character, hope. - Romans 5:3-4

Joy comes in the morning.

May the God of hope fill you with all joy and peace as you trust in him, so that you may overflow with hope by the power of the Holy Spirit. - Romans 15:13

We aren't promised freedom from sadness. We're promised joy in spite of it.