What to do when your paper journal disappears
"1. cry
2. cry some more
3. sit down with a piece of paper and write down every to do that i can think of that wasn't completed"
"Curl up into a ball in the corner and sob uncontrollably."
"Go to the pub!"
If you decide you are going to live the analog life when it comes to journaling, I highly recommend you find a method of archiving and backing up your paper that works for you. Whether it's digital images, scanning, or just copying things down somewhere else, having a Plan B for your information is the only way you can truly have confidence in your system.
When it comes to a technical method of backing things up I use two different tools: my phone and my printer. I can never be sure when I will have time to capture the contents of a notebook so by using my phone to capture scans to Google Drive (my storage system of choice) I can feel more confident things are there should the worst case happen. My printer comes into play because when I purchased my printer I specifically bought one that allows scanning directly to Google Drive (see the plan coming together?) With the printer on hand, I can scan page after page of journal and other documents to my library with no risk coming from the loss of the physical materials.
There are many different ways to back up your analog journal. It isn't nearly as important how you do it as it is that you do it at all. Don't be the person crying in corner of the pub because the dog ate your journal. Be prepared.