Looking for the start of this harrowing adventure?

Oh dear.

If you're lucky, you can raise a support ticket with your mail provider and hope they have a backup of your email and that they can restore it. Sometime in the next week.

Perhaps you take your own backups. Hopefully it's not too hard to work out how to restore those without wiping out your remaining mail archive. Hopefully.

Worst case, it's all just gone.