I have a fishy smell down there and don't know what to do there is no doctors office open on Sunday please help

Could be old menstrual tissue or yeast infection. Any chance of a tampon left in there?
No need to rush to an ER. Don't douche, but do keep washed with soap and water, and if it's still there tomorrow, and you are sure nothing's in there or you aren't due for your period, go to a drugstore and get some Monistat.
Other more remote possibilities are trich (pronounced trick), another kind of infection, and some sort of cyst that is leaking, like from an ingrown hair.

A "fishy" smell usually indicates bacterial vaginosis. No need to run to the ER, you can wait until the doctor's office is open.