Period please help! I'm worrie idk what's happening

I took nuva ring out Saturday I got my period 3 days later, (yesterday) and it started light but then went from red to dark brown and dark red, it's not spotting though it's just like a heavy period. Is this normal? I don't take it out every 3 weeks I skip periods sometimes. So is it just old blood? It's quite a bit. I just wanna be sure I'm okay. Please help!!!!!