The actual emails were not sent from your PC or your BlackBerry. It has nothing to do with your BlackBerry or even the brand of computer have you.
The emails were sent from some server across the ocean spoofing your name as the sender. It happens every day, billions each day, without anyone's computer or BlackBerry being hacked. Servers run combinations of server generated names on popular domain names (aol, hotmail, yahoo, google, etc.) and send mail.