I upgraded to Yosemite last night and seem to have lost over 1000 photos.  I looked at the photos count at the bottom of the screen in Library–>Photos view before upgrading and it was about 14,300.  After upgrading its about 13,100.

I did do a back up beforehand.  What is my suggested next course of action to a) confirm there are definitely photos missing b) retrieve them.

Manually comparing my back up to internal hard drive files seem like a lot of effort.  I’m not really sure how to go about doing that either.  Any help would be appreciated.