u/Aggravating-Shop4806

I use my Kindle scribe to take notes for almost everything in my life. And I was in one of my biggest notebooks earlier today and it popped up and said unable to sync last changes, Click OK and I clicked okay and then continued to go on with what I was doing. It wasn't until a minute or two later that I realized everything in my notebook was gone.

How do I get it back? Is it gone forever?