Last month I started my period on 17th April and finished on 21st April. This month I started experiencing signs of my monthly period on thurdsday, 10th May 2012. Unfortunately, I had unprotected sex on 11th May 2012. 15 hours later I went to the clinic and I was given Microgynon 4 tablets start and then after 12 hours I took the remaining 4 tablets. However since that time, I still experience nausea and I have not had my period up to now. Worse still, I do have severe abdominal pains or is it cramps; I went to the hospital today and I was told my pregnancy test is negative. Does this mean I am pregnant but it is at undetectable level? Has the microgynon disturbed my cycle that I cant have my periods now? What are the possible causes of this abnormal pain? I am sure my body prepared for the period and I was supposed to start but I have not?