Spam email sent from my email account

Why is Norton 360 not protecting my email account.  Spam emails have gone out to all my contacts.  Do I have a virus?  If so, why did Norton 360 not protect me.  I NEVER open an email and click on a strange link and I know I did not do this.  How could this have gotten to me.  I am on Facebook and have a Blackberry and have wondered if either of those sources could allow someone into my email. 

There is a specific Forum for Norton 360 so I'll ask for your message to be moved over there or better exposure. You won't lose sight of it because a link will be left here.

Hi lkpreston,

 

Do you use an email client such as Outlook, or do you use a web-based service such as Hotmail or Gmail?  Are you showing the spam messages in your Sent folder and have you gotten any bouncebacks from recipients that are not in your contact list?  Have you responded to any emails from any of your friends or contacts asking you to click a link to see photos?