I would try changing your password ***** logging off all devices here: https://www.facebook.com/settings?tab=security§ion=sessions&view
Did that link work?
I never said it wasn't. I'm suggesting that you change your password ***** log off all existing connections at the link I provided because it's sounding like there is possibly a rouge device connected to your account.
Were you able to do this? If yes, did it solve your problem?