Cloud, what a fantastic relief. Such good news! I am so pleased for you. I hope this means you can go on holiday and really relax and enjoy yourself.
Thanks, everyone, for being so kind and thoughtful. It did me the world of good to go out into the garden, and the sun. Then I went out for lunch with my sister and just felt more positive. I realised that having an enlarged yolk sac may mean I have a 1 in 3 chance of poor outcome, but those odds are actually better than the odds I thought I had before having the ultrasound, which was 50/50 chance of miscarriage at my age. Now that I have seen a heartbeat, my odds for miscarrying have lessened.
I have decided to organise another scan, but probably not until 9 weeks (by my dates) as that is when I have miscarried before,and it would be good to see what's happening in there at that stage.
Also, an enlarged yolk sac doesn't always mean miscarriage, it may mean chromo issues, but it also may not. It's all very unknown. I also realised that it is my job to love and honour the child I am carrying, not to allow comments made by careless health professionals to have me give up on my child.
Then, driving home yesterday evening a funny thing happened: I had to stop to let a row of ducks cross the road.It is uncanny, as my doctor had said over and over at my first visit, that "all my ducks were in a row" and she had a good feeling about this pregnancy. I wish she wasn't away for 4 weeks, it would be good to talk to her about all this. The fact that,after having an ultrasound report say something very worrying, "associated with poor outcomes", the Dr I talked to and the practice they work for didn't offer me any support whatsoever ("wait and see"), which I think is very poor. I will be having a word to my Dr when I see her next.
I also started feeling quite sick in the evening, which means there must be something going on in there 
Grizzer, it sounds like not being too sick is probably a good thing for you? The scan was reassuring wasn't it? Do you have another scan planned?
Welcome Monkey.I am very sorry for your loss. Hope your wait for a BFP is short.