Welcome to HCM,
You potentially had unprotected sex and took emergency contraceptive
Bleeding in such cases usually due to withdrawal of hormone along with abdominal pain
it may last for 2-3 days or spotting.
These hormone tablet can cause some irregularity in menstrual cycle.
If bleeding is heavy and severe pain
it is better to consult a Gynecologist for proper assessment.
Your question seems old one as dates have already passed.
You should practice safe sex as it prevents both unwanted pregnancy and sexually transmitted disease
Please take care.