Good suggestions from SBT, especially about the Alpha Male. Getting your Test levels running more efficiently can be a great first start to feeling better all around.
You also might want to try Surge Workout Fuel to drink during your shift. It’s not stimulant-based so there’s no crash afterwards. It’s designed to support long physical activities (like marathons, hiking, big workouts, etc.). Loading and unloading pallets and packages for hours at a time would definitely qualify.
You can sort of think of it like super-improved Gatorade that isn’t just sugar and sodium. It has leucine, which is an amino that helps build and preserve muscle, it has a more complete hydration blend, and it has nutrients that can help improve endurance and recovery.
Finibars would be another way to keep your energy up during work. It’s designed with specific carbs to boost performance and recovery while being very light on the stomach and digesting quickly.