Speaking of Heads

At risk of repeating myself, can I just mention (again?) how much I dislike psychosomatic chemotherapy symptoms? Today is as far as I ever get from chemo infusions and pills, yet by noon I was already starting to feel all of the crap that I'll be feeling for "real" tomorrow when my infusions are finished. 

What evolutionary advantage could there possibly be to feeling crappy in response to an experience that hasn't happened yet? Prompted by the psychosomatic symptoms I could refuse the actual chemotherapy treatment, but that hardly seems a strategic choice if one's goal is to survive. 

And it seems to me that it really ought to be the case that once you realize that the symptoms are psychosomatic that should be enough to effectively turn them off. I mean, if you know it's all in your head, shouldn't reality adjust around that awareness?

Apparently not, because I've felt like crap pretty much all day and there's absolutely no reason for it other than anticipation over how the chemo will make me feel, and it's bad enough to have to feel that way in response to the drugs but to feel that way just because your brain seems to want to is annoying as hell.

If I've got to have an imaginary friend, why couldn't I get the six foot tall invisible rabbit instead of the twenty-four hours of imaginary chemo effects?