Hey Guys! Yes I also found it strange that my doc tested me so early! 10 days post et....which made me more nervous.... maybe because I did an FET? but in my clinic they always test on the 10th day! And YES whats important is that HCG doubles and the most important still is the ultrasound!!! I think even if you dont test your HCG after the first, as long as they see the sac when its time and then the yolk, etc. then youre OK.
I dont want to scare but based on my experience...just to share, and you will see that Ive experienced a LOT!! In the end what you see during ULTRASOUND is what will matter most! This is my 6th try 1st IVF = BFN, 2nd=BFN, 3rd= BFP but mc´d 10th wk, 4th= BFP - ecto!, 5th= BFP - ecto again!!! and now FET= BFP- so far so good....As you can see I had 2 ectos!!! and during that time my HCG started low! but doubled well!! so I thought everything was OK...in the end it was the ultrasound that told the truth....no sac and yolk when there should have been one.... which caused concern for my doubling HCG but nothing in the womb....So dont panic as many still deliver healthy babies inspite of low HCG levels but then wait til Ultrasound....
Good luck to all of us then and please update on the outcome.....remember each person is different and I know so many miracle stories.....just dont panic, enjoy your BFP and just live day to day in peace

It will happen too with determination and faith!