You can be sad and still have joy. I heard this recently and I started to understand joy with a new perspective. Happiness is an emotion but joy is rooted deeper than that, it's a way of thinking.
When my daughter was diagnosed with a kidney disease this summer, I decided then I will seek joy in every circumstance. I can be sad, but I can still have and seek joy.
Seek joy my friends!
Nehemiah 8:10 for the joy of the Lord is your strength.