Possible hack attempt what do i do now ?
If you recieved an email telling you someone loged in from a different IP address and it was not you, change your password ASAP. That means the person who logged in has both your username and password. The only thing stopping them from taking over your account completly was that email authentication.
Also, add authenticator to your GW2 account if you have not.
Change your password to the game and email from a seperate computer/network. Not your current one. Then before you log in to the game or forums, do multiple DEEP scans using a few high rated anti virus and malware scanners.