Sounds like a spammer is using your email address as the sent address for their junk. If they already have your email address and are using it there is nothing you can do to stop it. Be protective of your personal info including your email address. Do not post it in public locations. Even then the spammers seems to find a way to get it and use it. Read about backscatter here. http://en.wikipedia.org/wiki/Backscatter_%28email%29