To me, prayer is the only thing that has really 'worked' with my Invisible Diseases. Not discounting the doctors (I am one), but seriously. They simply can't know everything. But God does.
The Rosary, in case you are not familiar with it, contains several Biblical prayers in it. There is The Lord's Prayer, the Hail Mary, and The Profession of Faith. You start at the crucifix, and the beads that are alone are The Lord's Prayer. Then you move your fingers and grab one of the next ten beads, which are 10 Hail Mary's in a row. Then another Lord's Prayer by itself. Then another 10 Hail Mary's, etc. until you are back at the Crucifix again.
Personally, I find great comfort in saying the Our Father because Christ taught it to the disciples as an example of how we should pray. It is The Lord's Prayer, and it reminds us to forgive, and that we will be forgiven as we forgive others. It reminds us to give thanks for our daily bread, which reminds us of how God took care of His people by having manna fall from the sky. I find great peace and stability in praying the Rosary.