How long can i go with out peeing before having to go to the doctor?

i just had a baby and ever since she was born i haven't been able to pee. its been about two weeks and i have already had five catheters put in. today i just got it taken out and i was told if i don't feel like i emptied my bladder with in six hours to go to the emergency room and get another catheter put back in. but its already late and im tired n was wondering if it could wait till tomorrow morning?