How could i be 5 weeks pregnant on 5-11-14 if i conceived on 4-17-14 wouldn't that make me less than a month pregnant?

Dating a pregnancy: Many times, women do not know the date of conception. For this reason, pregnancies are dated from the first day of the last menstrual period. This is usually about 2 weeks prior to conception. By convention, If you are 5 weeks pregnant, you are really about 3 weeks from conception. Conception is a bit tricky as well, It may not happen until a few days after you have intercourse.