Real talk about jobs:

-If you are sick, you are sick. Period. (hehe) If there is no one to cover for you, that is your manager's issue to deal with. It does not matter what the reason is. You. Are. Sick. and will not be in.

-The store will not explode if it is not open for a day.

-If you were to keel over and die, they'd immediately find a replacement. Don't bend too far backwards for them. Ever. Unless they pay you double.