Ok I'm very confused to how many weeks pregnant I am when I calculator it says I'm 5 weeks but technically I am only 3 weeks I had unprotected sex on the 2nd of March my last period was on the 12th of February how do they actually work this out because technically I'm only 3 weeks when I had unprotected sex and that's the day I ovulated so how is it saying am 5 weeks when I didn't have sex 5 weeks ago