Okay, this might not be helpful, but I'll try anyway. Do you by chance feel your brain is perceiving all linear movements as more than they are? Do you find running to be uncomfortable?

I'm not a doctor, and even doctors have their own theories about these this, but I'm going to tell you what happened to me and what ive been told, in case it helps.

After an initial concussion, I have had a series of "neurological events" that have mimicked a concussion, caused new symptoms, and set back others. All were caused by sudden movements (like tripping and falling), and I feel as if my brain is perceiving motion in an amplified way. I often described this as "feeling like my brain is sloshing around in my head". Just to be clear, as far as I understand, its not possible to feel your brain (these head movement sensations are created from inputs from the vestibular system). When these sensations are amplified, they can be extremely uncomfortable, but they are just sensations. Not damage to the brain. And as far I I know, the mechanism for causing concussion is stretching of the cell axons, which physically opens up gates in the cells to cause ions to rush in and cause an energy crisis. This requires a lot of force. BUT the symptoms of a migraine event can be very similar, and can be triggered by overload of any sensory input(s). I saw a leading doctor who told me when people seem to get "concussions" from minor jolts to the body they are actually getting migraine attacks triggered by a sensory overload. Migraine is common after concussion, and sensory sensitivities and common with migraine (light, sound, and even vestibular/movement signals can get amplified). You don't need to get headache to get migraine. Anxiety is a VERY common side effect of migraine. Vertigo is also common with migraine. You don't have to have headache to get other migraine symptoms, and you can treat migraine with medication. I suggest reading a book called "Heal Your Headache" by a famous migraine doctor and see if your symptoms fit into what he describes.

Like I said, this might not be what you have, and every doctor has a different opinion, but I figured I'd put it out there...worth a shot, as you seem to be really struggling.