Just spotting or period

This is kinda weird for me to talk about but I had sex on Friday but then I think I started to have some spotting on Sunday but I don't know about Saturday & I haven't really stopped spotting since but it's been light till today I was in the bathroom & a bit more came out then usual so i don't know if I'm on my period & im not suppose get my period for another 13 days....what do I do?