Imam Ahmed, Musnad (1/391), and others reported upon the authority of Ibn Mas’ood that the Messenger of Allaah (sallallaahu 'alahi wa sallam) said: “No slave is afflicted with anxiety and grief, and then says:

‘O Allaah, I am Your slave, son of Your male slave, son of Your female slave. My forehead is in Your hand. Your judgement upon me is assured and whatever you have decreed for me is just. I ask You by every name belonging to You which You have named Yourself with, revealed in Your Book, taught one of Your creation or which You have preserved in the knowledge of the Unseen with You that You make the Qur’aan the spring of my heart and the light of my chest, a banisher for my grief and a reliever for my anxiety.’

Except that Allaah will replace his distress and grief with joy.”

He was asked, ‘O Messenger of Allaah, should we not learn it?’ He said, “Ofcourse, whoever hears it should learn it.”

Authenticated by Shaykh Albaani in ‘as-Silsilatul Ahadeeth as-Saheehah (1/198)’ with a slightly different wording. And this wording was delcared hasan (sound) by Shaykh Ali in his checking of ‘Fawaa’id al-Fawaa’id pg. 49

This is my favorite dua and boy have I needed it over these last few months!