Hi, I've experienced some spotting 5 days after an oddly long period which lasted 8 days. It began light but gradually became heavy. My period is regular, with a 28 day cycle. I had unprotected sex with my boyfriend 2 days after my period ended which was 3 days before the spotting began. We havent had sex since two weeks prior to the spotting which was before my last period. What could be the reason for the spotting?