Expert answer:
Generally pregnancy (fertilization of the ovum occurs within 24 to 72 hours after intercourse), may have become pregnant in either of the two relationships you had, by calculating the date you would have gotten pregnant on 04/16/11 with a miscarriage 10 days before or 10 days later, then you can not be sure, though the first ratio seems to be the most likely.
Yes the morning after pill may have failed but may have gotten pregnant in the relationship in which there was no ejaculation inside.
