I am 28 months post injury. All of your above is familiar...too familiar. Have any of your doctors, neurologists, etc. ruled out a occipital spinal nerve injury, compression, or scar tissue building up around it. This nerve around your C2 can have far reaching and high numbers of unwanted results if your head and neck are moved (forcefully) into a position not good for it.

your greater occipital nerve runs very close to your optic nerve and can mess up the signals...

neck movements, even slight from exercise, to even walking and the impact transferred up to your neck can cause this occipital nerve to become inflamed and then maybe 24-36 hours the inflammation takes its course.

and everything plays catch up.

You were much farther along than I ever was at 6 months. Regretfully, all head injuries are different. every last one.

I went to multiple neurologists, multiple therapists, to the point where I was eventually diagnosed with a somatoform...(see s phychiatrist...its in your head...mental)...After 21 months or so...I finally found a neurologist that in under 30 seconds of hands on proved something decisive. Search neurotalk for "occipital" and you may find some more info. My profile info has my story...

gl