I have a 31 day cycle, and i had unprotected sex on day 21. he didn't finish inside of me, but i still took a morning-after pill. am i likely pregnant?

Pregnancy?: "Plan B" is not 100% in pregnancy avoidance. Even if the male does not fully ejaculate, there may be sperm released in the pre-ejaculatory phase. With a "31 day cycle", ovulation occurs on about day 17, but the egg can still be viable on day 21. If you do not start your period, wait a week and get a serum HCG test from your healthcare provider. May be time for more dependable birth control.