Can anyone tell me why I feel so much more confident with a cold/flu

[Nickf]

Hi,

   I'm 39 and since my early 20's, I find that whenever I'm fighting a
cold/flu virus although I suffer physical and mental malaise, anxieties take
a back seat.
    As a consequence, my thinking is more concrete (not easily
derailed/distracted), I'm more eloquent and consequently, more sociable and
confident.
    I understand that immune/CNS pathways are bi-directional, but nearly all
research focuses on the effect of psychosocial factors on the immune system
rather than vice-versa.
    Your thoughts please.

Regards

Nickf