Wow, your symptoms are likely chemo brain, similar to PCS as the anesthesia poisoned your brain. A PCS patient can be very susceptible to anesthesia. You likely had isoflurane administered. It can be brutal.

I have lost a little bit of cognitive skills each time I have been under for ortho surgery. It was rough on my father when he had a prostatectomy.

The surgeons like to use it because it causes the abdominal muscles to relax.

I have never heard of phosphorus being used to speed up healing from a concussion or such.

I would definitely get into a mega nutrition supplementation for the near future and possibly longer. B-6, B-12, folic acid, Omega 3's. Do a search of these posts for nutrition. We have discussed it at length. A blood test for B-12 and folate levels will tell if you are deficient. You want to be at the high end of the normal range.

Amitriptyline is considered a better choice for sleep issues. Nortriptyline does not have the same level of sedating effects.
BTW, Both are tri-cyclic antidepressants. Amitriptyline is commonly used for PCS and usually at small doses such as 10 mgs.