did i start my period?? TMI

!!

i've been on antibiotics and during that time i also missed a pill but i just took two the next day. after i finished the antibiotics (10 days) i came home from school and was spotting. then the next morning i woke up and was pretty much on my period but this whole time the blood hasn't been red, it's almost so dark that it is black looking? i heard it could be old bloom but i'm confused