If i concieved may 4th how many weeks would i be june 18, 2013? what week do i start counting? thanks

Confusing sometimes: When you hear someone's pregnancy referred to as weeks, it is counting from the first day of a person's last period, not from the conception date (people are more likely to know the former). And, since you ovulate on avg 2 wks after that day, the weeks you hear do not truly represent how long you have been pregnant. With that said, if you conceived then, you are around 21 weeks now. About 1/2 way.