So .. I'm only diagnosed with ADHD but also live with the assumption of being autistic which means: I recognize overload-patterns with me and follow autism-advice which almost always improves my situation.
Now I have this peculiar problem: Most of the time I work from home (which is great!) but every few weeks I have to show up at the office. On those days I get up an hour earlier than usual and take the train to the city where the office is. The journey consists of 20min bus ride, then about 1h of train and then 2 subway-rides and 10min of walking. I got a routine for that, so it usually is no big mental load.
On those days the stress-meter of my Garmin-Smartwatch is constantly at peak values. On the next day I'm always tired and drained, no matter how much sleep I get. (below you should find a screenshot from the app)
I already have noisecancelling-headphones which I wear during the journey and whenever I'm working alone in the office. Working alone in the office while listening to music on the nc-headphones is similar to my work-situation at home, but the stress-level still stays at peak.
I also try to do breathing exercises and try not to cram too many meetings and other stressful-work-items into those office-days. And I try to have the train journey as comfy as possible, my employer pays me a 1st-class-ride and I usually use this time to relax, listen to some podcast / read / watch a film or do some work which I consider as interesting/funny, like reading about some new technology. None of this seems to improve the situation. The stress doesn't go away.
As rising earlier usually ain't that much of a deal for me (I sometimes have weirdly early remote-meetings) and as the people I meet in the office are the mostly the same as I'm having videocalls with all day when I'm at home, my suspicion is, that it is the fact that I'm not at home but at another place which causes this stress.
So do you folks have any additional advice what I can do on those office-days to be more relaxed / less stressed / less burned-out?
Not sure of this fits your Usecase, but bringing some kind of precooked stew to work might fit it. Some sort of lentil stew could work, as you have both protein and fibre. If you need something readymade you can buy at a store, then it could be something highly preprocessed like protein bars and such, which I would nod advise to have in your diet all the time.
Back in the days before "The Incident"(tm) when I was a regular at the office I often had one of those whole-meal-shakes like Plenny/Joylent which covers both protein and fibre and doesn't take much time to make. But tbh: Having a proper meal with colleagues is important and can be good for your psychological well-being. If you are the weird shake-gulper this might work less good. ;)