Completely understand what you are going through. Concussions in 2013 had me questioning that as well.
I still have ptsd from those days. The migraines that would last 2-3 days at a pain level 10, the fatigue, brain fog and exercise Intolerance.
Stay at it, most of your symptoms will probably improve through time. It took me about 2-3 years to be 90 percent recovered. The 10 percent of lingering stuff (exercise intolerance, bumps to head and heat intolerance) I’ve mostly gotten used to at this point.