Hey mommies ! Good morning / afternoon ! I have a question . My job requires me to lift bags and go…

Hey mommies ! Good morning / afternoon ! I have a question . My job requires me to lift bags and go up and down numerous stairs . The heaviness of the bag varies through each order. When should I tell my job that I can't work anymore? Btw my job is season . I only work during baseball season and I only work when there is a home game