Cause of our joy!
I think it was Bl. Mary of Jesus Crucified who liked to call Our Lady Shepherdess. I like that title as well. It gives me joy.
I also love the image of Divina Pastora - Our Lady the Holy Shepherdess.
Devotion to Our Lady, who is called, 'Cause of our joy' - for obvious reasons, fills us with joy, even amidst the greatest sadness. Try it. Recite her Office, or go aside and pray a quiet Rosary while meditating the best you can on the mysteries - even if it just entails looking at the pictures of the mysteries. If you are really little - just recite her litany. If you do not feel anything, or do not notice that you feel different afterwards, you will at least notice an inner peace... a joy unfelt, if you will. Although I am quite sure, Our Lady will not disappoint you and she will fill your soul with a joy the world cannot give. She always does.
Spiritual sloth - the vice which begets rancor, contempt and sadness.
Although perfect love should be disinterested love, no human being is capable of sustaining such love - our human nature needs the consolation of spiritual joy - which is the 'fruit of generosity in the love of God.' Disgust for spiritual things - authentic piety and devotion - when willed, may indicate the spiritual ill of acedia, or the grave sin of spiritual sloth. Not to be confused with the trial of spiritual aridity of course.
To conquer spiritual sloth, a good, frank sacramental confession is the first step. Spiritual sloth is overcome by genuine love of God exercised in true devotion of the will - authentic piety - which includes mortification and the practice of the virtues. Even when sensible devotion be lacking - that too can be offered as a sacrifice in reparation. So can migraines and other debilitating illnesses.