Albums are in backup library and photos in Photos library

Hi wizard_chef,

Thanks for using Apple Support Communities. I can see that you report a behavior in which your pictures are suddenly located in the default Photos library folder on your Mac. I can understand that is certainly bothersome, but I will be glad to offer some suggestions today.
Recreating or organizing pictures and events is certainly a time consuming task, therefore I want to suggest that if you have a recent backup of your computer in a Time Machine Backup, you can try to restore to the latest copy of that information. Keep in mind that the backup you restore will have the information that you had in your computer at the time of such backup but not newer information.
For more info, please review this article:
How to use Time Machine to back up or restore your Mac
Also, you can locate in your previous backup just the Photos library file and attempt to restore that library file:
macOS Sierra: Restore items backed up with Time Machine
Otherwise if you don't have a backup of your information, you will need to re-import your files in your library.
Hope this information can help you.
Regards.

It sounds like you have created multiple libraries - hold down the option key while launching Photos and test each library in the resulting select library window - hopefully one will be the library you want

LN