Dark/Black Blood

Caitlin

Okay so I was due to start my period yesterday and missed. I got prematurely excited thinking i was gonna have a BFP and then AF decided to show up today. Weird thing is...it’s very stringy, extremely dark, and not a ton but it would be light for me. So what could this be?? Just a regular period? I didnt have implantation bleeding with my last & idk if it’s too far for that. Any advice??