spotting or implantation bleeding

hey y’all! i had sex on 2/5 (dead center of my ovulation week ) and today since about noon i’ve been on and off spotting. it’s been heavy enough to leave a stain in my underwear and has yet to completely stop. i’m on the patch for birth control, but he’s unsure whether or not he pulled out 😡 my period should start in 8 days. i’ve got no other typical early pregnancy signs, only some mild pain in my lower back which is typical for my cycle. what are we thinking? early spotting or implantation bleeding??