The norm for whelping is between 58- 63 days,give or take a few days either side.

If she's yelping I would get the vet to give her a quick once over and maybe a scan to make sure everything is normal.I wouldn't leave her alone now just incase she starts and got into any trouble and needed help.
Make sure you have your vet on standby just incase.

Let us know how you get on...