Had sex one week before period. 5 days delayed but got brown discharge and 1 day period. what does that mean?

Pregnant?: If you are not using any type of birth control, its possible you are pregnant. Discharge and a 1 day period doesn't sound like a normal period and could be pregnancy related bleeding. You should get a pregnancy test. You can get one to do at home at a pharmacy without a prescription or see your Ob. There are other possibilities such as an anovulatory month. Best wishes!