One important fact mentioned on the Mayo Clinic site was that often when the affected person learns there is a cause for his/her symptoms (Post-Concussion Syndrome) and that they will improve with time they are likely to feel better about themselves. And again for a better description "not all in your head" or like someone that is not quite right...as you mentioned "crazy". (Many of the symptoms you mention are quite common.)

Again; this is just going to take time. Once you realize this will improve; it will help lessen the anxiety and improve sooner than later. I can understand your frustration; but nothing is so drastic as to feel the need not to go on living.
You have your whole life ahead of you. After this has improved, you will realize life is worth living.

Hang on tightly; you will be okay.


Gerry