Solved
Horizontal mouse inverted bug
To explain the title, yesterday I came home to turn GW2 on, my mouse has horizontally inverted itself. (When move it left, it looks right and vice versa.) This only happens INGAME, when I press ESC ...
After stuffing around with the options, it seems somehow the keybindings have reversed, and I had to guess what Axis Y 0 was and select it for left and right.
All fixed.
