Ohhh, butterfly :-( I'm so sorry to hear that. I brings me back 2 years ago. The same thing happen to us. You go there and wait for the heartbeat to come and than there is a empty sack. What a disappointment and pain in the heart. I had pregnancy symptoms until about 10 weeks, but no development.
i really hope it will still turn around and start growing!!!
lots of and good luck for next weeks scan.
you are still lucky that you fell pregnant and that you still have some waiting. Hope you can fix your immune issue, because than it really needs to work!
thinking of you....