Strange period

Hello!

I had a normal period. It lasted 7 days, which is a little longer than my normal periods, but it has happened before. Then, the day after it ended, I had sex. Later that night I started bleeding again like my period started again... I use a tampon, didn’t need one the next day but I’m still spotting. Anyone have any ideas as to what is going on? I know I have PCOS, and I’m having no symptoms of anything else.. it’s just like it started back up immediately after sex, and hasn’t gone away since.. thanks for reading :)