It has taken several days but my library is back. The original problem remains regarding the odd date and time sequence. But all 38,000 pictures are back. When I called Apple they said I needed to bring back my Time Machine library and use that one. My iCloud.com pictures were also deficient in numbers by 25,000 on my MacBookPro. Oddly, the cloud pictures were slightly different by a dozen pictures back in 1970. In any event, I did not erase my library nor restore my backup from Time Machine.
I went to work and opened my MacBookAir. All my 38,000 pictures were there! Oddly, on Safari/icloud.com all 38,000 were also there!
When I got back home and opened my MacBookPro and went to Safari/iCloud.com the pictures were not there.
I know you are going to ask but yes I was using the same login information.
I called Second Tier support at Apple. They said they could see the 38,000 pictures. We went to Photos/Preferences and unchecked the box for PhotoSharing. Then we went to SystemPreferences and logged out of my iCloud account. Rebooted. And reversed the steps.
Two days later my pictures are back and my iCloud looks fine regarding photos on the MacBookPro.
Still cannot understand why my pictures are not in order regarding date and time given same time zone but I can live with that.
Thanks, Leonie!