I can only imagine how frustrating that must be. The problem with the body clock is that the rhythm seems to need to be constant, everyday needs to be the same. So while some days you sleep at night, on your nightshift you’re completely out of sync again and vice versa. As someone who used to do nightshifts, I can only sympathise. I know there has been a lot of research into the effects of working at night for nurses. I’ll have a look and send some over if it helps!