Dude ..

.. of couse you have to worry.

I mean if you want those parts intact. Your spleen will be the first to go. It will rupture in the first brawl on the streets of the Bronx. Next should be your kidneys, acute renal failure from dehydration, since you'll be so swamped with work you'll not only have no time to drink fluids, you'll have no time to think about it. And next one to go will be your aorta, secondary to high BP in turn caused by all the 36-hour-shifts. Whether that will produce an aneurysm that'll soon dissect or whether you'll just get a plain old heart attack - that's the real question. Not whether you should worry. Especially not about the little 12G-needle stuck in your back.