Use your commute time to go for a walk (lockdown permitting). Shower before you start work and dress smartly enough for a casual day at the office. Get out at lunchtime for a run. Keep your work hours roughly the same as they would be in the office if you can.
Also it can feel good to feel like the hottest version of yourself. So at least a couple of evenings a week, dress up a bit, as if you're getting ready for on a night out or a date. Shave/trim. Moisturise. Pluck. Do your hair. Pick something from the fanciest bit of your wardrobe. Nicest underwear. Spritz of cologne!