What Causes Vaginal Bleeding After Taking Postinor-2 Followed By Protected Sex?

Hello doctor. My last period ended on the 28th of last month, i had sex with protection on the 6th of this month with protection but the condom broke, hours later i took postinor 2... I started vaginal bleeding yesterday and it hasn t stopped till today. Am really bothered and don t know if it s a period or what.