implantation, period, or bleeding after sex

i ovulated 13 days ago and my period is due in 2 days. 15 days ago i had protected sex. i had protected sex again today but it was the roughest i’ve ever had. a few hours later i noticed that my panties/shorts got a blood stain. when i wipe there’s not that much blood and it’s pretty light colored for me—no solid flow yet. is this my period a day early, a result of irritation from rough sex, or implantation bleeding? obviously time will tell, but any advice?