Pre-cum touched my vulva. then took plan b 15 hrs after. i got my period 2.5 weeks after plan b and it lasted 7 days. does it mean im not 100% pregnant? do i need to take a test?

Take a test if you want (sounds like you will). The chances of you being pregnant if the things you describe are true approach zero.

You are not pregnant, however, your behavior is putting you at risk of pregnancy and STDS. Visit this site for guidance on safe sex: https://www.hopkinsmedicine.org/health/wellness-and-prevention/safer-sex-guidelines Get HPV vaccine Use contraceptive all the time, every time. Wish you good health!