I realize your post is a warning and not necessarily looking for input but I can't help myself.
"The PS crossing the blood/brain barrier and dropping my cortisol allowed the virus to get in and is now wreaking havoc" I'm sure this is the explanation your doctor gave you, but to me he is just grasping at straws.
Your withdrawal was hugely stressful. Consider that this stressful experience and the resulting immune system deficiency is what allowed for a thriving environment for the virus sort of like how one can get the common cold.