I don't know what's happening!?

This month i was late for my period by 5 days and usually i'm never late. Earlier today me and my boyfriend were having sex and he was using a dildo on me and then i started bleeding so i assumed it was my period, he wasn't weirded out by it or anything he just asked if i was okay and if i needed anything, i had the usual cramps and everything the week before so i figured my period was just a little late and i thought it had finally came today but i've already stopped bleeding which is not normal at all for me.. and i have no idea what's happening. and it also hurts not like cramps but it feels like throbbing down there and i don't know what to do...