I feel "normal" (for me) now. I'm having a G&T, didn't drink anything but water yesterday. It's like your immune system announces to the body:
"Hey, boys, I need your attention here, gonna have to draw on some reserves, y'all might be feeling a bit tired for a bit. Some kind of strange in the works."
I think that is Good News, in effect. If I see the real thing, Immune System will say:
"Heh, I know this trick. Saddle up boys, time to lasso some virii."
Shirely, "we" have to be exploring this technique for other vaccines. I wonder if in five years we'll be getting shots galore. My doc said I should get a pneumonia shot annually now, as well as flu.