Regarding anxiety, as far as I know, both hypoventilation and hyperventilation can affect ear pressure. Hyper I think off the top of my head decreases ear pressure. I'd need to check that though.

I get a feeling of fullness in my ears and head when my vertigo is bad. I can always tell it's coming on badly when that "full" feeling happens. I know what you mean. I think it's called - aural fullness.

You haven't mentioned balance issues, so it could be that you need to learn to breathe properly which in turn may help the anxiety issues you have developed regarding possible concussions. Just a thought anyway...