Hi Charmed -- welcome to allnurses.
I loooooooove my ICU night shift job. You don't say how long you've been doing this... is this new and you're just adjusting? Or has it been a long time?
Now for the hints (nothing you prob don't already know, just getting the behaviors in place is the hard part:
1. Hydrate well. I bring a small cooler with bottles of water now, dump ice over them to make it a treat.
2. Eat well. Healthy light main meal, lots of veggies, healthy snax (sliced fresh veggies, fruit, granola, low fat cheese/crackers). DON'T graze from the vending machine.
3. Avoid the coffee (and other caffeinated drinks). Acidic and likely contributing to the nausea, belly ache, and dizziness. Also makes it difficult to sleep when you get home.
4. Make a small ritual of relaxation when you get home (quick soak in the tub, quick shower, massage your own temples or feet, spend time with your cat/pet, quick relaxing nookie LOL, whatever helps you rest).
5. Get 30"-60" of exercise when you wake. It'll give you energy for the day once you get into a rhythm (if you don't exercise now, build up slowly). Walking is great and centering.
Well that's a start. Let us know what else we can do to help!