Album is Empty , still says # ofof photos on the side bar. Photos are can be found in All photos.

Hey everyone, hope you can help with this. Basically I was going through my workflow when all the sudden the album i was working on says there are no photos. On the left side it did show the same number of photos that were in the album, and i checked the All Photos album and they photos i was working on were there, all edits saved. When i drag the photos back in to the album, the number of photos increase but still says album is empty!

Can you please help resolve this as this is very inconvient to the workflow working with hundreds of photos :(. Thank you.