While having sex on Saturday, my bf hit my cervix a few times. Period was due on Sunday. Sun morning, started to have some lower back cramping, and some stabbing pain (almost like bad constipation pain, it was the same area feeling, but inside, on the vaginal/colon wall). Still have that pain, still no period, and definitely not constipated. Is it possible that he bruised my cervix, and that it swelled up enough to not let menstrual blood through? I have charted my period for 6 years, I ve been late 3 times in that stretch of time, and am normally early. I m getting a bit worried. I had a tubal ligation after my second child was born, 8 years ago.