Hi. I Just Bleed 2 Weeks After The Intercourse, As

Hi. I just bleed 2 weeks after the intercourse, as well as my period. My boyfriend and I assumed that it was safe. But since last week, I feel nauseous and having light cramps. (But not all the time.) And just yesterday, I am having a light discharge and it's not my period yet. My date is 2 weeks from now.