Emergency pill gives more than 95% protection against unwanted pregnancy
within first 24 hrs. Here, chance of pregnancy is NIL as you did safe sex just after period over.
Now, you are getting withdrawal bleeding due to effect of the pill and it usually stops within 3 to 4 days. Prolong bleeding may be due to hormonal
imbalance and you can take Tranexamic acid
drug to arrest bleeding.
Your period may be delayed for 1 -2 weeks from due date due to stress and hormone ups & downs. Practice safe sex in future and use contraceptive