Isaac of Syria once wrote to his followers encouraging them not to fall into despair. His words were more in line with feeling desperation for our sins, but I feel that his words' do not despair' are also true for us in all other circumstances.
“Do not fall into despair because of stumbling. I do not mean that you should not feel contrition for them, but that you should not think them incurable. For it is more expedient to be bruised than dead. There is, indeed, a Healer for the man who has stumbled, even He Who on the Cross asked that mercy be shown to His crucifiers, He Who pardoned His murders while He hung on the Cross."
2 Corinthians 4:8 - "We are hard pressed on every side, but not crushed; perplexed, but not in despair."
Living in Grace