The e-mails are the returns from the infection spread by someone who knows you. basically the virus sends itself from a PC but uses another e-mails as the return address.
So Alice's PC is infected and knows Bob. Alice's computer sends the virus to Charlie but it uses Bobs address as the return (sender) address. Charlie thinks Bob sent the virus. In the case that the mail server auto returns virus e-mails Bob receives the messages being returned and not Alice.
Both you and i and thousands of others are suffering the same. If you have up to date AV and you've scanned don't worry.