I may have accidentally deleted an email in Outlook, so how do I sort by the last item I deleted?

Good question. It may seem strange because you can't easily sort by a last "modified" timestamp by default.

Here is how to add that field of information as a column in your Outlook view:

1. It only works in "Compact" view, so confirm you are set to this view, even if only temporarily.
   Then click "Manage Views"
   
2. Select "Compact" again, and then "Modify"
   Then click "Columns" and select "Date/Time fields" from the drop-down.
   Then select "Modified" and "Add" it to the view.  Click OK and you're done.
   
3. You should now see a Modified date column that will reflect when the item was deleted.