VERY TMI

I didn’t get my period for September and I just got my period this month for October yesterday (that was my first ever missed period I’m 17) I also had some ovary pains for 4 weeks now 1 week it was horrible pain now it’s casual here and there pain .......now I got my period for October and by blood is kind of black and coming out in large chunks or kinda floating on water as if oil was in it or sinking to the bottom Im weird pieces (not a miscarriage)