Thanks for the query.
As you had intercourse on around 5th or 6th day of periods the chance of pregnancy
And as you took the pill after 72 hours the protection is doubtful.
Emergency pill will alter the menstrual cycle depending on the period when you took the pill.
So the bleeding you are having could be side effect of the pill.
So you wait for few days possibly by that time bleeding will get controlled. If not consult gynecologist and take tablets to control the bleeding.
For more details you can ask me through: http://www.healthcaremagic.com/doctors/dr-sree-gouri-sr/63429