I had my periods last on 6th september last. after that i have had unprotected sex with my partner on the 15th of september and again on the 2nd of october. I took emergency contraceptive pills - two , one the 16th of september and another on the 19th of september. Sice then till today the 26th of october i havent had my menses. i took an urine home pregnancy test today on the 26th oct, and it shows negative. what are the other possible reasons of my menses being delayed. Please help.