Too bad you already had the MRI. A SWAN MRI would have been interesting.

I've probably said this before but my first concern is your sleep. Sleep can be impacted by your neck or other discomforts.

It sounds like your brain is being overloaded. Poor sleep makes your overload threshold much lower. The original injury may have also reduced your overload threshold, maybe permanently. But, you can maximize your threshold with an understanding of your brain's limits.

What are you daily activities ? What activities/tasks cause you the most struggle ?