I had unprotected sex on the 16th day of my cycle. i was afraid of the pre semen. i took plan b after 3 hours. will it work? i have a 26 days cycle.

It should work: Plan B works most of the time, but not all of the time. One should do a home urine pregnancy test 3 weeks after Plan B. Also, use reliable forms of birth control so that Plan B will rarely be needed (hopefully never) in the future. If cycles are a very-regular 26 days, ovulation is probably on day 12, which means by day 16 the egg is dead (but life can surprise you sometimes).