Mmmmmm

I was 2 days late for my period and the blood is brown when I wipe it’s a lot of brown blood and sometimes it’s red blood in the middle of the day sometimes . It’s like light brown in my pad but the blood is brown . It’s been for a day now is it my period or spotting?? I took a pregnancy test before my period and it said negative but I also had took a plan b after my unprotected sex .