My math isn't adding up...

ChevyFam717

OK, I am probably just obsessing over this but I am getting a bit worried now? Can anyone tell me if this makes any sense? Warning ? lots of info and might requires some thinking? First day of LMP ? May 18, 2012 Note: Intimacy Dates ? June 9, 10, 11, 17, 20. BBT Spiked and stayed up ? June 12, 2012 First BFP ? June 25, 2012 Blood BFP ? July 6, 2012 First Ultrasound ? July, 18 2012 (Baby is measuring at 6 weeks 1 day- HB 128 BPM) Due date - March 11, 2012 (Based on ultrasound calculations) Based on the due date provided by the ultrasound (going on calculation of baby?s size) the conception date would have been June 20, 2012.   This would be fine, except how could I have gotten a BFP only 5 days after conception when I POAS? Everything says it should take 12-14 days to get a positive urine test?   I guess I am just kind of worried that I conceived earlier and baby isn?t measuring up to par? They did find the heartbeat and said that any heartbeat at 6 weeks is just perfect and everything else seemed normal, but I am worried that the dates just aren?t adding up and the next u/s isn?t until 18-20 weeks, which is still 10-12 weeks away!!! Next apt is in 2 weeks which they will try the Doppler, but I am just a bit confused at this point? Any help is greatly appreciated.