Ok I have this problem about my vergina n I bleed for a day n then stop n then bleed black stuff sort of like a period but not if you get what I mean... What should I do? Help

I have a period for a day n then stop n then bleed black guwee discharge what should I do it's sort like a period for a day but not if you guys have any clue what it might be then please tell me many thanks... I'm not a vergin but I have not hAd sex for 2 years :D

How old are you may I ask?