“O God! Refresh and gladden my spirit"

O God! Refresh and gladden my spirit. Purify my heart. Illumine my powers. I lay all my affairs in Thy hand. Thou art my Guide and my Refuge. I will no longer be sorrowful and grieved; I will be a happy and joyful being. O God! I will no longer be full of anxiety, nor will I let trouble harass me. I will not dwell on the unpleasant things of life.
O God! Thou art more friend to me than I am to myself. I dedicate myself to Thee, O Lord.
Baha'i Prayers, A Selection of Prayers Revealed by Bahá’u’lláh. the Báb, and Abdu'l-Bahá pg. 152

This is my favourite prayer, I read it when I get down..... on myself.