First of all, keep in mind that I am unable to diagnose you because I am unable to examine you, this forum is for educational purposes.
Pituitary dysfunction after traumatic brain injury (TBI) is very common. Some studies have suggested that 25% of TBI patients with have post-traumatic hypopituitarism (PTHP). Some of the neuro-psychiatric complications of TBI such as personality changes, aggressive behavior, depression etc are now thought to be contributed by post-traumatic hypopituitarism (PTHP) (was previously thought to be due to 'axonal shearing' alone that occurs during the injury- probably both contribute to these changes). It sounds like you are having the appropriate testing and I hope that supplementation may make a difference for you.
I hope this has been helpful.