Just don't panic. There is a good chance you can still get to them.
First, check the History - in the upper right corner on the dials page. This can be related to issue with downgrading Beta or Nightly versions, see this article:
If you don't see backups in history, maybe you have created cloud account or have a backup file exported?
If you see any error on the dials page, please let me know - you can contact me directly to my support e-mail.
Most of these bugs is related to some Firefox bugs. My add-on cannot loose data by itself... Also it's used by 50k users so such issues would be reported by many others.
Have a nice weekend.