
I can't see any photos but by 7 weeks, you should be seeing puppies moving around, unless she's carrying a really big litter and they don't have much room to move, or she just has one or two, and is carrying them up under the ribcage still. At day 60 they should be starting to move down.
I had one of mine who at around 5 weeks, looked suitable big. But she didn't really increase much in size, and in the end, produced one puppy! I think she may well have reabsorbed others, much as there was no sign of this (and the C.Section didn't show anything either).
I think all you can do is give her up to a couple of days beyond her due date, counting from the first mating, and unless she's in trouble before then, and get her examined by your vet. He may give her a shot to get things moving, and/or x-ray to see what's going on.