Calson,
One thing that I've always read about Brain injuries, is that One, leads to another, leads to another. And, THAT is NOT good.
You don't seem to have faith in your doctors, and, Emergency room doctors aren't set up for TBI.
And, Further, YOU HAVE NO WAY OF SUSPECTING INTERNAL BLEEDING!

You need a really good neurologist, who specializes. Are you near a city with a good University Hospital? Get to the Cheif of neurology. Sometimes you really hafto dig, to find what / WHO you want, NEED.
Don't give up.

What you say is true. If you have had a concussion, you can't really know the extremity of the damage, and especially with more than one. That takes a clinical psychologist, in my experience, and testing. (Not scans, tests like school). Although, an MRI maybe ordered.
CT scans use very little "cancerous" radiation.

Notice any personality changes? Ask someone who has known you all your life.
Outlook changes? Think about it. Friends disappear? Lost relationships?

There are some really good books on Amazon, and they have the readers comments, as well.
One or two may be right for you. Just search TBI, or head/brain injury.
Investigate. Learn.
You'll be better off for it.

That's what I can tell you for now, I sometimes wish I had a magic wand, but I don't.

Keep the faith, and carry on.

Best to you,

ASB
Pete