Can someone tell me what happened?

Sammie
So i had my period 14 days ago and i had sex shortly after it ended multiple times. I usually use some type of protection but i did not this time and he did not pull out during any of the times we had sex. We both knew this put me in risk of a pregnancy but for some reason i just got my period. Not only is it over 10 days early but it was also a surprise. Do u think there could be any explanation for this?