
This is exactly why I don't scan!! It only confirms a pregnancy at the time of the scan (which may be enough if there was an 'accident' and the need to spay or not, made), not that the bitch will carry to term. And in any case, even if I'd been told no pregnancy from a scan, I'd still be waiting and hoping.
If she was mine, instead of all this scanning, provided she was otherwise fit, I'd have waited until around the due date, and gone for x-ray. Which is what you might yet consider re this 'sticky vaginal discharge'. She may need help (medication) to help scatter her milk assuming there are no puppies and cut back a bit on the amount of protein she's eating?
Very sorry for you because it's so disappointing. I had one who looked okay, big, at around 5 weeks, and then didn't expand further. At least she had one big bitch puppy (how often are singletons male!!) and clearly reabsorbed any others she originally had. That bitch wasn't as good as I'd hoped either, much as we still kept her. No showing or breeding for her tho.