Help!

My boyfriend and i had sex lastnight and today when i went to the restroom i noticed i was bleeding. It wasn’t alot but it wasn’t little either. We didn’t have rough sex or anything and ive never had a problem like this before. Also my last cycle was June 18-23. I looked on goole to see if it could be implantation bleeding but it says that wont happen a day after sex. What could this be?