Spotting after sex

Well two days ago me and my bf were having sexual intercourse after we finished, I went to the bathroom to pee and when I wiped I had some light colored blood on the tissue so automatically I’m thinking my period is here but NO!! It was just that on the tissue but no cramps no more blood for the rest of that day until the night time hit and I started to experience cramps. But still even after two days no period. Could I possibly have went through implantation? Or something else?? Btw my cycle is 4 days away from today