
It really depends on your bitches behaviour etc. & there is no way of knowing what she is doing without actually seeing her.
Early stages of labour can last a long time, but once in established labour things should move fairly quickly. To define the difference of early stages & established labour is impossible on a public forum.
Have her waters broke? Any contractions? Loosing any vaginal discharge? Has she had a temperature drop?These are all clues as to what her body is doing!
You don't say how many days she is post mating & how many matings she had, this info is vital.
It wouldn't hurt to get the vet check her today.- Good luck, hope she's ok. :)
edit to add ~ just wondering why she was scanned a week ago? Most people would scan at 28-35 days. If your bitch is now near her due date, she must have been scanned at 8 weeks?