Emails permanently deleted?!

As I was using Thunderbird, my inbox listing started to scroll as each email was deleted in turn. I exited as quickly as possible, and tried to recover the mail from the Trash folder. I was able to move some emails back to the inbox, but the most recent emails were permanently deleted. I connect to Gmail using IMAP. When I checked there, the permanently deleted messages were gone from there as well. I'm not the best typist, and may have hit some strange control-key combination, but this was a *really* bad outcome. I thought I had a kind of automatic backup by storing messages locally in Thunderbird as well as in Gmail. Seems as though my emails were being deleted permanently on my computer, and then that was reflected back to Gmail. But I did not delete any of those emails myself, and certainly didn't bypass he Trash folder (if that's even possible). Of course I may have just done some brain-dead thing, but perhaps this will give other people a heads-up?