ANYONE KNOW WHAT THIS COULD BE ??

I had sex 5days after my period then I started to spot 6days after I had sex does anyone know what this could be it lasted for 3 days and then stopped my period isn’t supposed to start till next Friday ….(wasn’t a flow I kept a liner on after I seen a little dot from day 1 because I thought I was tripping because I didn’t see anything after but the second day I had a splash and that was it for the day same for day 3)

Day 1

Day 2

Day 3

Gone..