Am A Lady I Had My Menstruation On The 23rd

Am a lady i had my menstruation on the 23rd of last month it ended on the 28th of last month, i met my man on the 7th of this month we had unprotected sex and i took postinor 2 few minutes later that same day, now i ve not seen my menstruation, could it be that am pregnant or could it be there is a delay via postinor2 that i took