It sounds like someone hacked into the facebook password server and stole passwords. If you think your yahoo email has been compromised I recommend you change your yahoo address and password as well. Try not to give out your personal email account online, but save it for your friends and family, and use an alternate email account for online registrations, etc that you can change if you have problems like this.
Identity theft is a major problem these days, with many people losing information because their computer has been compromised in some way.
It would be worth your while to set a password on the user account on your computer, to make sure no one can log onto your computer as you and use your saved passwords.
Also, go to www.malwarebytes.org
and download their free antimalware program and run a full scan of your computer to make sure your system has not been compromised. Fix any problems it finds.
I hope this helps you to resolve this problem. If I've managed to answer your question, please take a moment to kindly rate this post....thanks!