My hubby & i have an 18 mth old.in the heat of the moment tonight did not pull out. i ovulated yesterday according to my app that i have used for years & have used to get pregnant with our daughter.how effective is plan b the day after ovulation?

Should work fine: Plan B can be taken on any day of a woman's cycle, so that a woman does not have to think about which day of her cycle it is. Plan B works most of the time, but not all of the time. One should do a home urine pregnancy test 3 weeks after sex. Also, use reliable forms of birth control so that Plan B will rarely be needed (hopefully never) in the future.