What Causes Irregular Periods With Cramps And Brown Discharge?

Hi, can you please help me, i am 22years old i have always had irregular periods , i haven’t had a period since june, went doctors last week and the doctor thinks i have got polycystic ovaries, I am waiting on a date for a scan to confirm this is what i have, but today i have had really bad cramping pains near my lower stomach area and i have also got brown discharge i would if u can tell me whats up and if you think i need to go doctors tomorrow or wait for my scan date? Thank you sarah.