Hey Freezerdoor, have you done vestibular therapy?

The problems you are having sound similar to what I went through. In vestibular therapy we started by walking slowly on a treadmill and looking at pictures in a magazine. Gradually we worked our way up to running on a treadmill while rearranging a deck of cards.

All of this stuff is super easy now, but at the time it was a real challenge. The idea was to retrain the brain to focus while bouncing up and down.

So I guess I'm saying maybe it's vestibular and vision?