get your second wind
get a/(one's) second wind
To experience renewed energy after a period of fatigue. I'm sorry, but if I don't get a second wind soon, I'm going to bed. I planned to stop working at 9, but then I got my second wind and just kept going.
get your second wind:gain a new strength or energy to continue something that is an effort.
get your second ˈwind(informal) find energy, strength or enthusiasm after feeling tired or after a period when you produce little: After midnight the dancers seemed to get their second wind and went on till dawn.
This expression comes from running; after feeling out of breath at the beginning of a race, you later find it easier to breathe.