OK, there's something else I want to say, and I'm going to be blunt. I think the symptoms you describe are not hopeful. On the other hand, sometimes it seems impossible that a pregnancy will continue and yet it does.
You may remember that I got pregnant three months before conceiving my dd. I was completely ecstatic and kept retesting just for the joy of finally seeing that double line. Then, after a week, the second line started fading. The next day I went to an EPU to be scanned. I'd been there ages before I asked them, "Could I possibly still be pregnant?" and they looked at me like I was mad. I realised that there was no question for them that I could be, that falling HCG levels only mean one thing, and that their only concern was to check it wasn't an ectopic pregnancy. It was a horrible feeling.
Three months later I got pregnant again. Six days after my positive test I couldn't resist and tested again. The second line was fading. You can imagine how upset I was. I kept retesting that day and next morning - different tests taken at different times - and they consistently got paler and paler until the second line all but disappeared. This time I didn't bother going to EPU, just shed my tears and waited for the bleeding to start. But it didn't start. And two weeks later, feeling I was losing my mind, I went for a scan and there she was.
I still don't understand how it is possible that I didn't miscarry a second time, and no-one has been able to explain it to me. But I also think the whole of this fertility and conception business is essentially mysterious, and we have to live with a great deal of uncertainty.
Why am I telling you this? Not because I think you shoudl have unrealistic hopes. But because there are situations - like the one you are now in - when it is truly impossible to know what is going on, all you can do is try to still your brain as much as you can and do whatever you can to get through the days until greater certainty is possible.
I've probably been no help whatsoever but please know, Becky, that you are in my thoughts. You really deserve all the good luck in the world.