
I guess you just wait & see now.
You could have her scanned, but you'd have been better off getting that done at 28 / 30 days post mating.
You could have an x-ray, but there isn't much point & I would never have an x-ray done just to confirm pregnancy.
Just prepare for the whelping & the litter & watch her over the next week. Some bitches will hide the pups well & not look pregnant, or she could just have 1 or 2 pups.
Or she could be having a phantom
Good luck.