On you messages window when loading AC you will see an 'Inbox' drop down in the upper left corner, just to the right of the patient list. Click the down button, 'Inbox' is an option.

You can click on any message and retrieve it back to your inbox if you've accidentally sent it to the wrong staff member. BUT, I believe restarting AC will wipe out your 'Sent' box and will clear your 'Deleted' box.

HTH