I Have Unprotected Sex With My Wife,we Have A Baby

I have unprotected sex with my wife,we have a baby of 7 month. She misses her period usually it comes 12 of every month.now its 21 ,after that we did pregnancy test which comes positive.
Today's its 9 day, i have taken postinor2 and white quinine today by 6am up till this hour it remains the same pregnancy, how much it will be effective.
Is it safe to have to a brest feeding mother...