"I feel hopeless... I am a failure... I cannot keep going anymore... It is not going to work..."
Felt and said by me or you, do not worry, it happened to the best of prophets, to people who actually met God himself.
The bible tells us about Elijah, when he felt worthless and felt that he is losing the battle against the priestess of Baal. Then God, Who was always with him, even in the dark times, made him win, over his enemies, and over his fear and sadness.
Always remember, God will be with you, even when you don't need Him.
God will give warmth, peace and power... just believe...