brain rot!

...bit of an odd thought to push its way through at the height of my exam panic (36 hours to go), but I'm suddenly seized with the fear that large swathes of my brain are in danger of rotting away through disuse.
When I recall my teenager-hood, it is usually with much relief that I will never have to live through it all again. But despite the traumas - broken friendships, never being in the 'in' crowd, (perceived?) parental and teacher underappreciation - I have to admit that my mind was almost always sufficiently stimulated. Physics special paper tutorials used bits of my brain that have definitely fallen idle now; I was practising for my piano diploma, submitting poems to an online poetry guild, playing tennis with my dad at weekends, reading books. And I could actually speak chinese. At university (apart from Medicine) I edited a magazine, learned photography, and read the bible for the first time from cover to cover.
Why is it that when we grow up and start work, it all falls to pieces? (Or is it just me?) My work has taken over my whole life, and I flop, drained of energy (particularly if it's been an 08:30 to 21:30 day) into bed each night. It's almost like Charlie in Flowers for Algernon. And it's way scarier than, say, a former athlete losing muscle tone - at least they can keep tabs on it by looking in the mirror. I can't even begin to assess the damage to my neurons caused by more than a year of neglect. This exam with all its memorising has been more mind-numbing than stimulating. (I am conscious that you may have little sympathy for my situation - what? being a doctor not mentally stimulating? - I assure you, it isn't, not much. Emotionally taxing yes, every day. Intellectually stimulating, perhaps once a week.) Am I in the wrong job? Maybe. But I live in hope that the balance will shift...
AND I need to learn something completely new before it is too late!