Bookmarks "reset" while synchronizing

somenumber

somenumber

I've had many bookmarks (for movies etc.), but I never synced them. Today I turned on "Sync Everything" and it synchronized my Bookmarks with an earlier version of my Bookmark list. In some folders, some bookmarked websites are missing, some things I've removed from my bookmarks have appeared again. Weirdly some Folders (and their contents) I've created not that long ago have stayed, so it seems to be not that consistent.

I doubt it but, would there be any way to recover my old Bookmark Bar before I synchronized everything?
Thinking about it, I'm not completely sure if anything is missing, some things just seem to be out of order, but if there is a way to revert this "sync incident" it would be great.