Whether or not you can recover it will depend on a couple of things:
Are you using a POP3 mail account? If so, are you using a PST? If you are
then read this:
http://www.howto-outlook.com/howto/restoredeleteditemsfromanoutlookpst.htm
Are you using an Exchange mail account (this would normally be in a business
environment)? If so, does your Exchange Administrator have Deleted Item
retention turned on? If she does, you can open your Deleted Items folder.
Once there, click on the Tools button and scroll to "Recover Deleted Items."
Highlight the email and recover it, it will be returned to your Deleted Items
folder.
