Hi. I Had Unprotective Sex With My Bf On 13th

Hi. I had unprotective sex with my bf on 13th March. After few hours on the same day, i took postinor 2. And the second pill 12 hours after that. After 5 days, i had bleeding. Its not like a period blood. It's light and odourless. Today is the second day of the bleeding and i've been having stomach pain like a terrible period pain. Is this a withdrawal bleeding or just a normal period. My normal menstrual cycle should begin another 2 days on 22 march.