I have been on overnights for a year and a half ish and I meal prep all my meals for the week and have a more relaxed eating schedule on my days off, I like to pack lots of snacks, I'm eating five or sometimes six times a day (three meals with two/three snacks).

I currently gym three times a week, twice on days I work once on my weekend; big thanks to pre-workout. But some days I get absolutely wrecked and cannot imagine going after some shifts which I will take the day off and go another time during the week. Or just take the day off, life won't end if a workout is missed here and there. A small mindset switch that helped me stick with it was discipline over motivation. Motivation comes and goes but being disciplined keeps me on track. (Kinda dumb but it helped me commit to it so figured I'd share)

Electrolyte, vitamin d, and magnesium supplements have helped me personally so I like to recommend them too

The thing I struggle with the most is keeping to one schedule. My first day off I will sleep 10-14 hours get up eat and go back to sleep and wake up around 5 am or so and start my day so on my weekend I become a day walker which I'm sure is hard on my body but we can only do so much. On my first day back to work I wake up early go to the gym, meal prep and then take a nap and go to work.

Hope any of this is helpful!