Am I spotting or my period is long?

So last week sometime I had sex, the next day in the morning I wiped and it was like a little light colored blood. The next couple of days until today I’ve been wearing a tampon but the blood coming out is really light and the amount is a couple drops.. so I took my tampon out for a couple hours and went back to the bathroom and it’s still coming out with some of the blood being dark brown and it’s been like 8-9 days?! The app originally said I was supposed to start my period the 13th aswell.. how long are you supposed to spot for? Is spotting for a week normal?? Or is my period gonna be 2 weeks :/ idk if it’s spotting or my period. (I’m also on bc but I’ve been on birth control since last year)