Opinions wanted please

I was due to start my period last Thursday. Did not start until Saturday morning. Had cramps that morning and bled light-moderate Saturday and Sunday (2-3 regular tampons on those days). I have now had spotting Monday, Tuesday, and today. Had some mild cramping on the way to work this morning. Took a pregnancy test Friday and it was BFN. Any opinions that I could still be pregnant? Or I’m just crazy? My periods are normally 4 full days.