I had sex with my boyfriend without a condom 8 weeks ago. I got my period last time and it was 3 days and very dark old blood. I am currently on day 5 pf placebo with no period. I dont have any symptoms really but am so scared. I took 3 pregnancy tests and are all negative. I keep hearing those weird stories about how someone didnt know she was pregnant. Whats the cause of me missing my period? I have skipped it in the past by skipping the placebo. Is that the cause? help!!