Google Nexus 5 :: Pictures Randomly Disappear?

So last week I was off on March break with my family and I took several pictures Tuesday and Wednesday on my phone of my kids, even remember showing a few of them in the evenings to my wife. Realized I forgot to turn on "auto backup" to google drive (or whatever it's called) and turned that on at some point mid-week.

On Friday I went out with my son and snapped a few more pics, and realized all the pictures I had from Mon - Wed were gone. Not in the Gallery app, not in the Photos app, and now that I'm checking with a computer, I simply can't find them anywhere on the phone at all.

I certainly didn't go through each photo and select "Delete" or anything like that! Unless there was a delete all button that I somehow clicked accidentally (which would seem really odd) and deleted all photos from the camera itself (it's a new RMA'd camera so all I had were the photos from Mon-Wed).