I can't understand that it is a sign of pregnancy or not??

Helo everyone,Actually My periods is 11 days late nd i feel pain in my lower abdominal nd some times in my back just same as that i feel before periods.Can any body tel me that is this also be a sign of pregnancy?Because when my periods are about to come den 7 days before the due date of my periods i feel pain in my lower abdomnal pain,backache.So I can't understand that it is a sign of pregnancy or not??