My Facebook sent messages to everyone on my friend list by itself?

[Kare Bear]

I'd say run a virus scan for your computer, and go through your facebook add-ons and make sure nothing was added you didn't mean to. Or if there's a sketchy-seeming app, then remove it. Most likely, your account was hacked, and changing your password was a good first move. Make sure your password is complicated and has a mix of capital letters, lowercase letters, numbers and characters. It will keep your account more secure. Don't click on links from facebook that people give you, unless you're 100% positive the individual meant to send the link.