Joy is a fundamental disposition toward God. What characterizes Christian joy in contrast to happiness ... lies in its ability to exist even in the midst of suffering, because joy has less to do with emotion and more to do with belief. It does not ignore pain in the world, in another's life, or in one's own life. Rather, it goes deeper, seeing confidence in God--and for Christians, in Jesus Christ--as the reason for joy and a constant source of joy.
Unlike ephemeral happiness, you can cling to joy even in the rough times. Joy is happiness in God and you can carry that with you always.
I hope you find joy today.
For another post on joy, see: http://lansdownebaptistchurch.blogspot.com/2014/06/sharing-joy-found-in-our-faith.html