Someone elses virus attatching to your e-mail addy?

No virus on my machines, any of them. No virus sent to anyone in any of my e-mail address books.
But here's the thing. I open one account in particular and almost every day for a few weeks there were 7 - 15 "returned mail demon" things stateing that the e-mail I sent had a virus attatched to it. I have never seen the attatchment they reffer to, nor is any of the e-mail addresses that weren't delievered to anything in my address books or anything I recongise (all business ect - non seem to be a peronal name).
Any clue? can a virus attatch itself to your e-mail address and send it self from someone elses computer with your e-mail addy attatched to it?