cheryl..i totally agree with mumstar, i reckon you O later so you not as far along as your AF due date would be, this has happened to me not with blood tests but with early u/s when i think im 7 weeks only to go in and they cant find a heartbeat, but im only measuring over 5 weeks, but it has all turned out ok for me, when i wasnt as far along as my LMP date......i wish you well