Hi thanks for your question.
Bleeding after emergency contraception
that is I Pill
is usuall but flow and duration is highly unpredectable.As for as drop of blood before I Pill is concened it could be due loacal trauma during sex.This bleeding is not your menstrual cycle bleedin but because of I Pill..If bleeding doesn't settles down in anther few days consult a gynawcologist who may be able to examine you and may prescribe appropriate treatment.
Hope this answers your question.