Email was hacked last night

Hello everyone. My email was hacked late last night, it had something to do with a craigslist spam that was a response to an ad I had posted. The weird thing is that I receive these spam emails all the time, and I NEVER click the links that are in the email response. This time was no different, I did not click the link, however, my email was somehow hacked just from opening the email. The hacker targeted my entire contact list, as well as anyone who I've ever emailed. I apologize to anyone that received a spam email from me late last night, if you did receive an email from me please DO NOT CLICK THE LINK from the email, I do not want any of you to fall victim to one of these low life hackers that have nothing better to do but mess with peoples lifes and personal information! Yahoo told me that they have recently fixed security issues that were resulting in peoples emails being hacked for the past few months, I call BS! I will most likely be switching from Yahoo to Gmail to avoid any future situations like this. I will also be editing my craigslist ads to have people use a keyword in the subject line so that I know it's a real person, I urge all of you to do the same. I apologize if any of you received spam from my email last night, I assure you that it was not me.