pls give me the courage to call out of work😭

i work at a daycare center taking care of 3 yr olds. i like my job but y’all i’m mentally and physically exhausted!!! my sisters have tried to convince me to just call out tomorrow and rest but i kinda have a hard time doing that cause i don’t wanna let anyone down. can y’all please give me the courage to call out tomorrow? plus what excuse would be great to use to call out?

update: i was honest and told them I needed a mental health day and called out! thank you to everyone who gave me feedback