+ hpt today!!! YAY!!! How far along am i?

the first day of my last period was July 23rd, and i got a positive reading from an ovulation tester on 8/6 and a positive hpt today, 8/17. I calculated my due date using my period and it was april 29th, but if you count backwards from then that would make me 4 weeks which can't be right. So which is it???