if it were me
supplement with melotonin before you go bed
supplement casually with vitamin C and D
eat meals during ur shift when it suites you
try avoid caffeine if ya can ( i know difficult)
bring your own meals so you dont snack on junk
go gym after ur shift if u still have energy so ur wrecked and sleep better after ur workout,
or go gym before your shift to wake you up and give you energy, really wateva u find works better for you
last meal before bed should be a High G.I carb meal with protein, this is becoz blood sugar spikes and crashes are shown to increase the rate of how fast you fall asleep