Have you tried playing the game without your modification? Do you notice any difference if you play without it?
When I play the game its self, I'm running it from a separate install to anything with my work in progress or testing mod work on it. I've had a few graphics card detection problems with another game today however, so I'm wondering now if my card might be dying and causing it.
But I'll uninstall and reinstall FH this weekend though, see f it clears up (if not its the card for sure)
Thanks for trying to help though guys <3