[X4U] "New" spam technique

[nk]

Maybe just new to me...

I just got a piece of spam with the subject line:  "RE: You can be 18  
again!"

OK, nothin'  new there..spammers have been using the "RE:" trick for  
awhile.

but the from address?  one of MY addresses! Plus, they even used the  
little pic/icon I've used!!

is this just a step in the ever-changing evolution of spam technique,  
or do I need to be concerned that somebody has basically hi-jacked my  
email address?

n