You don't have a virus, at least not from those symptoms.
If you get a load of emails saying "message undeliverable" or simlar words then I'm afraid a spammer has picked up your email address as a bounceback.
When a spammer sends out thousands of emails to random addresses, they do not wish to receive a reply for each undeliverable one so they pick someone's name of the list (in this case you) and have any undeliverables returned to your address.
You can't do anything about it apart from wait until the spammer chooses someone else's email address.