Hi,my cycle is usually btw 25-28 days bt neva after the 28th day. My period came on the 9th of dec2013 n lasted for 5 days and I had an unprotected sex on the last day of my period,13th n I took postinor2 on the 4th day,17th. Now my period is due for today,5th of jan 2014,bt it didn't cum. What do u think is wrong? Thanks.