Why did this occur with my Yahoo! email account?

An email was sent to all my contacts with the subject title "Lynne Bradley" and a link included in the email. The thing is, I never sent the email. So, I'm concerned. Could my email have been hacked? The link was to some foreign website. The address: sp690002.w.interia.pl/Rhys.html. What do you think happened here? By the way, I was not on my computer or email at the time the email was sent.