Help Entire folders of pics missing?!

[engine]

So I opened my gallery and discovered five or six folders entirely GONE! I'm floored... I'm running stock lollipop on a verizon note 4. I've no other issues and I updated over three weeks ago. I don't use a lock screen...is it possible I butt deleted them? (like butt - dialing?) It seems really far fetched. I plugged into my PC but the folders don't exist there either (so they're not simply hidden in the gallery view.)

I'm at a loss.

any ideas?

 

[ronbien]

Best guess so far is that if you have an SD card, and store the photos on it, the card is going flaky and will soon crash. Get everything else off as fast as you can.
Good Luck!
Ron