What Causes Cramping And Brownish Vaginal Discharge?

Hi i was due to have my period on the 4th of June it didn't come , and then from the 6th to the 9th had heavy white discharge. On the 10th started experiencing light cramping and brownish discharge but today has become a bit heavy but nothing like my usual period. I'm not on the pill or any other medication am a healthy 30 year old