hi my LMP WAS ON 26TH OF DEC 2013,AND I DID NOT GET MY PERIOD TILL TODAY.ALSO I WAS TAKIING TAB.DEVIRY 10 MG AS ADVICED BY DR.FOR MY STOMACH PAIN DURING MENSTRURATION.BUT I HAD INTERCOURSE ON 2nd OF THIS MONTH.I AM AFRAID THAT I AM PREGNANT. IF SO HOW MANY WEEKS PREGNAT AM I?