Advice 🙄😂

So i was on the antibiotic azithromycin for 5 days, during my placebo pills. My last antibiotic was taken on the 18th. I started my new pack of birth control pills on the 18th (last day of my antibiotic). i had unprotected sex and he did not pull out the last two nights (19th & 20th) Should I take plan b or not? My predicted fertile window starts the 23rd. I’ve been on birth control for 6 years and haven’t missed a day. I also have PCOS and I don’t think I’m very fertile to begin with. I also read that azithromycin does not affect birth control but I just wanna be sure.