Sorry to hear that, it sounds like you will need to restore your forum from backup
I update my forum from my 1.1.1 to 1.2.1 version of nodebb. Now when I do login I obtain " invalid csrf token" and I don't know why. Anyone can help me ?
maybe you add a invalid url in somewhere.you can try to turn down the the port ,such as :4567,ban the port connection internet.and then delete what you added.
@Doppy This sounds like you have made changes to your database settings.
Check your Nginx settings. One of my systems broke on upgrade because of that.