Does anyone else notice this issue? Happens usually once a week...
If it happens even when you're on (for example) public wifi, then it's malware on your own computer.
It's funny because sometimes if I go to facebook.com, it pops up with an SSL error - saying the site certificate belongs to another domain (eg: nonfacebook.com). Usually a reboot fixes it.
It could even be something that infected your router, such things exist. http://it.slashdot.org/story/09/03/23/2257252/botnet-worm-ta...
You shouldn't take this lightly, and definitely shouldn't bank online or otherwise do anything that should require any kind of security until you resolve this.