Cannot import photos library

Ok so I accidentally deleted the photos library from my pictures folder but put it back from the trash. When I put it back it said there was already a file called that, so I said to keep both. My pictures folder now contains two photos librarys one called "Photos Library.photoslibrary" and another "Photos Library copy.photoslibrary".

The latter actually contains all my photos, which I can see in the folder "originals" when I select "Show Package Contents".

When I try to open the copy photos library (i.e. the real one), it comes up with the following message:

I have also tried deleting the non-copy version (i.e. the empty library), but in this case when I try to open the copy, it comes up with the following message:

I have also tried repairing the photos library through the photos app, but it seems to only attempt to repair the empty library.

How would I be able to get all my photos back into the photos app?

Thanks for the help in advance.