To those that might have been following this story: an update...

I followed Tashybabe's excellent advice. Tash - thank you!!! I really was over-obsessing and driving myself crazy. So I went MIA from BB and have been keeping myself very busy.

It actually turns out that when we went to our scan a week back we found the measurements were 6 weeks (should have been 7-and-a-half). We knew there were a few days leeway there due to suspected late implantation. But the sack was completely empty. No fetal pole or yolk (I think in the past this would have been referred to as a blighted ovum). I had an appointment with my Ob straight after the scan and he said there was no hope, that I would MC.

I have chosen to MC naturally. If nothing happens in the next few weeks I will go in for a D&C (my fourth). I am doing OK. DH and I have so much to be grateful for with our two beautiful children who are the light of our lives. I will not be doing any more cycles - my two recent FET's were remaining from our successful cycle with DS. I just couldn't leave those embies sitting there and not give them a chance. At least I tried...

Thanks to everyone for their kind support on this thread. It really helped me through a difficult time.

WTH x