Is dark brown discharge leading into a menstral cycle normal? pretty sure i'm not pregnant. is this anything to worry about?

If...: It all depends if the discharge also is present after the period is done and persists. This could be an infection and you should get a formal exam with a gynecologist in order to test you if this is the case. Could also be the beginning of your period which may start with scant dark looking blood and then turns to a more bright red tone as the period progresses.