What Causes Light Bleeding And A Delayed Period After Unprotected Intercourse?

hi, i had a question. Me & my boyfriend has sex like 2 weeks ago. he cumed inside of me & like 2-3 days after i bleeded for like 2-4. it was light bleeding after that i was suppose to get my period on april 22nd & i havent gotten it since. my last period was on march 22nd.