Missed period?!?

Hello all! I have some concerns about a missed period... I am a sexualy active 20 year old. My boyfriend and I have been together for over 3 years, I am I full time worker and student. Last month my boyfriend and I had sex right before I had my period. We did not use any protection and he did not pull out. A day later I recievd my period. I am currently 1 week late, and have not gotten my period. I took a pregnancy test this afternoon and ir was negative (not pregnant). Should I re take a test or is it too soon? I'm sort of freaking out.