Had unprotected sex on the 17th, a day after my period. Took postinor2 same day; first tab on the 17th and second tab 12 hours later. Noticed brown discharge yesterday the 23rd (6 days after taking postinor2) and today 24th I'm bleeding. Please is this normal? Didn't experience this the other two times I took postinor2 as ovulation had passed then.