Just a thought.
If you base your joy on your circumstances, you're building on sand.
If, on the other hand, you resolve to be filled with joy, then you are building on solid rock.
Instead of allowing your joy to be crushed by what's happening to or around you, build your joy from within, without regard to the situation, and remember that you've been adopted by God.
You are a child of God!
Why in the world would you not be filled with joy?