I feel your pain......or at least I did.
My Hannah just had a litter of four beautiful Biewer babies on 12-16. For at least 3-4 days before I wondered "is this it"...."surely this is it"....."today is certainly the day". She had me going nuts; belly had dropped, temp dropped, could tell/see she was having the very early mild contractions......but no puppies!! I worried a bit, but told myself that as long as she was not yet on or past her last due date, was in no distress, pups were moving & heartbeats heard.... nd convinced myself that she & the babies were fine. And sure enough they were - 3 males & 1 surprise female (xray showed 3 pups) all healthy & well.
I suspect & wish the same for you! Good luck.......or maybe she's had them by now???
Oh, also I think I've read that first litters have a knack for coming a bit later than expected.