I had an abortion of 8 week fetus in July 1st week and had my regular periods a month later in August. But after that I had sex and had an emergency contraceptive within 48 hrs. now I have missed my periods for September and October but I have taken 3 pregnancy tests which are negative. I have taken the tests stricty as per instructions and have made no mistake in reading the results. Are there any chances that I am pregnant? If not what are the reasons probable for my missed periods? Please help.