What Causes Vaginal Spotting After Finishing A Period?

Hi, i had sex 2 weeks ago 36 times in 3 days without using anything which isn't a god thing. I'm not due on my period for 2 weeks yet because i had sex the day i came off my period, but yesterday i starte bleeding, light spotting of blood all day like a pink/brown colour. Im just wondering could i be pregnant or is it nothing to worry about ? i have tender ovaries so fgured i can't get pregnant.