My dear friend, The chance and possibility of pregnancy six days after the period is rare however not impossible as considering the bleeding for 4-5 days, it comes to 10-11th day of the cycle. The egg is released 14 days prior to the next expected menses. After 5th March, you were expecting your menses on 30th of March meaning thereby that your day of egg release would be 16th of March. Egg has got life of 24 hours and the sperms are active for 72 hours. Hence form 12th March to 20th March is your fertile period. However, you have taken emergency contraceptive pill. This pill has good protective effect provided it is taken within 72 hours of the intercourse; I hope you have taken it within that period. The emergency contraceptive pills contain high doses of reproductory hormones - Oestrogen & Progesterone. Hence, menses may get delayed for few days as the effect of these pills. You may wait for a week and still if you do not get menses, you may confirm the possibility of pregnancy by urine pregnancy test and/or ultrasonography. Earlier, these tests may give false negative results. I hope your query has been answered to your satisfaction.