Plan B

Does Plan B work? I had sex on Saturday, around 8:00pm and i took the pill.. Monday around 10:00am. I start my period in 9days and my boyfriend and i had unprotected sex for about 1 minute because the condom slipped. HE DID NOT CUM IN ME.. he didnt even do the pull out method. also way before intercourse he went to the restroom and urinated for about 20secs long. does plan b work and does it work against precum. help