please help! Im such a brainless idiot!!?

Okay, so im 18 have just left school, and have been looking for a full-time admin job since april. i applied for a job last week and the woman phoned me to invite me in for an interview. the thing is i had just woke up and realising, it was for an interview, i got really nervous, so when i got off the phone i couldnt remember a thing she said! I know the interview is at 5 but i dont know if its 2moro or monday, and i obviously dont wanna phone up and ask, cause thatll make me look incompetent. Any ideas? xx