Joy is the currency of heaven. You’re supposed to have it. For the kingdom of God is not eating and drinking, but righteousness and peace and joy in the Holy Spirit. (Rom 14:16) To be in the kingdom without joy is like going into battle without armor. And the enemy knows this. He makes it his business to rob you whenever possible.
Our joy can disappear when life disrupts us suddenly or can slowly erode over time if we are not careful to protect it. If you realize that you are living outside of joy, take heart. There’s more where it came from. Make the decision to have joy. When the whispers from the enemy tell you that you don’t deserve it, tell him to shut up. Claim your position in the kingdom and take hold of joy with both hands.
Go to Galations 5:22. Joy is a fruit of the Spirit, and if you belong to God, then all the gifts are yours. Claim all of them while you’re at it. If the Holy Spirit is giving you insight into how your lost your joy, you may have to repent and change things so it won’t happen again. Tell God that you want His joy, then chose to be happy. Joy is yours. Take it back.
Another post on joy: Looking For Joy In The Wrong Places