this is what i pill states in its website : "You have 72 hours to prevent an unplanned pregnancy after unprotected sex. Pregnancy is established only after the fertilized egg attaches itself to the womb. This process can take 2 to 4 days. You need to act within this time frame to avoid the risk of pregnancy."
as far as bleeding goes consult a doctor..one cannot answer question on basis of assumptions..do consult a doctor and don't take chances..