How do you have confidence in a volleyball game?

like i have a game and im trying to be back on varsity and right now im not doing so well and i just don't think im good at it so i just need tips or help on how to have confidence in a game and in practice. And i don't want to quit because i believe im a strong person and i can play very highly but its just when i make a mistake its like the my coach calls me out on it and then while im still on the court, its like i just shut down because i feel bad because i made a mistake and its like i don't know how to like think above it and just fix my mistakes.