I Had Sex A About 24hrs Before I Took Postinor

I had Sex a about 24hrs before I took postinor 2... I realized I was ovulating that same day(the day I took the postinor),, i also had Sex 2hours after taking the postinor (with my husband) and he mistakenly ejaculated in me... Will the postinor work for the before and after Sex? During ovulation? Or what else can I do to prevent being pregnant?