 [ Symptoms ] 12 weeks pregnant due jan 20th last period april 15th had sex may 2nd and on april 15 during cycle whose father  i did pregnancy calculator i am guessing it is about 95 may 2nd but still nervous jan 20th minus 38 weeks equals april 29th 30th but had sex on may 2nd but than also took a plan b pill on may 4th about 45 hrs later and still got pregnant [ Disease ] does not matter which of those two days you got pregnant doctors count pregnancy from the first day of your last menstrual period