Period or pregnant?

Calender has been saying 9 days late. I had some light bleeding and brown discharge on the 13. Than again i had light bleeding on the 18 & it stopped. My period still hasnt came. Could it be a late period? My last period was on march 14. Also had unprotected sex on the 31 of march. Or 1st of April. It was late at night. 20 years old.. Could i be pregnant help