I've had my discharge for about a week now but I still haven't got my period yet. Why?

Your guess is as good as mine. Did you have unprotected sex at a fertile time? Go to your doctor and have a proper test.

How old are you? Is your period late, or are you just assuming that it should be coming because of this discharge? What sort of discharge are you talking about?

How old are you, how regular are your periods, are you sexually active, what type of discharge?

You did not provide enough info to even make a wild guess