heres an area ive delt with many times!

Ive done holiday retail at a mall
Store manager at a major retailer and also managed a movie theatre

first get your stress level down. cortisol is bad. Take breaks dont skip them, relax on your days off mabey even take a break from training.
Also eat protien all day. Even if its just RTDs or bars or turkey sands in tupperware, eat that crap all day. Dont ever go more than 2.5 hours without it. I know thats hard at alot of jobs but you can always sneak something if you have to in 20 seconds even (a rtd)
lots o complex carbs in the AM helps
a real hard one is getting that water in all day during a busy shift. I still struggle with that.
The more you delegate to your staff and the more you accopmplish through them the less stress you will have. Obvious stuff here but just throwin it out there . . . . . Be consistent, hold them accountable etc.
See where you can cut time in your schedule . . .
168 hours in a week. 50 at work, 56 at sleep, 10 -15 for transport etc
find you meal prep and training time in there somewhere so you dont stress about it. Once you make a plan youll stop stressin out about it.
Sometimes a HIT program with rest pauses will help if you need results but only have 30-45 min. Save the volume workouts for days off from work.
Good luck bro, hope some of the stuff thats worked for me can help you!
Brock Samson