You could have 2 imbalances running concurrently.
Nervous system involvement from the Amitriptyline and either EBV re-infection or other viral infection.
Beware that if you have been on antibiotics, overly stressed or have poor
nutritional intake, your intestinal flora may have been compromised.
Should this be the case, you must rule out candida (doctors normally don't check this), as it may lead to leaky gut syndrome.
Another thing to note is when someone has candida, nothing seems to work well, healing ability is diminished and susceptibility to infections is increased!
Quality Probiotics, Coconut Oil and an anticandida diet will help tremendously!
You can do a preliminary self-test for it-> Saliva/Spit test for Candida.
Sometimes, medical tests can miss it! Just be aware of that.
Don't accept the lab findings as final and conclusive!
I hope this helps.
Cheers,
Niko