If Carbonite saved your messages, they can be recovered. It may take a few steps, but nothing complex. If you have the files on your PC in IMAP, do NOT attempt to log onto the account. Instead, exit TB and use windows file explorer to locate your files at Imapmail\accountname and copy elsewhere for later restore. If using default setup, copy the c:\users\<yourid>\appdata\roaming\thunderbird to anywhere for safety. That may be your only backup, so placing also on a USB would be advisable. Once you feel the emergency is past, let us know what you have and we can assist. For now, the safety of you and your family is paramount. Take care.