Missing Notes

Ever since I started using my iPad my notes seemed to store in two different folders, one labelled "Gmail" and another one labelled with my actual Gmail address. I thought it was weird but it didn't matter as long as they were all there. Out of nowhere, however, the folder labelled "Gmail" suddenly disappeared, and I can't find any of my notes that used to be there. They are not in my Gmail account or iCloud either. Where should I look and how can I recover them?