What Caused Dark Coloured Spotting With Fleshy Discharge?

. I' started using nuva ring for 3 weeks and when I took it out for the fourth week for my period I left it out too long (2 days) because my period kept going and no one told me i was supposed to put it in exactly a week after I took it out. So after two days I stopped my period had sex, then put the nuva ring back in. Wore it for another three weeks and within those three weeks, I started getting really tired, nauseous, become REALLY nauseous at the smell and taste of sandwhich meat, my breasts started hurting, I've had terrible mood swings, peeing a lot, having back aches and sharp pain on my side, theres a couple others too.
So than this fourth week I took out the nuva ring and havent started my period its been 4 days now, but i did notice a little tiny bit of spotting that was a dark color and it was a little fleshy, WHAT IS HAPPENING!?