We all have times in which training and fitness are essentially the last thing on our minds, but if you’ve been active for a bit you’ll know just doing nothing whilst very busy can make the place a somewhat unpleasant place to reside in - aside from how you feel physically.
I’m just coming out the other side of some health problems, and can’t tell you how much of a difference it’s made on to just keep whatever little activity in that I can - even when it was a fraction of what I’d been doing. Training can be an outlet, a way to get some distraction or simply get a sweat on and enjoy the ensuing endorphins.
If you find yourself in this situation, keep it simple - work out how long you can realistically do something a few times a week, even if it’s not long. If you’re stressed and sleeping poorly alongside this (which I imagine you are), factor this in and don’t necessarily make this super hard. If you have a little more time to be able to get a generalised warm-up done (5 mins on an assault bike, jogging to the gym) you could get a bit more out of these, but they have warm-up sets built in. Here’s an example of a session you could do in 25 minutes:
Zercher Squat/Bench Press/Pull-Up OR Banded Pull-Up
You’ll need a rack, a bench (which can be moved) and potentially some bands for your pull-ups. Set the rack to a height that you can bench press out of, leaving the bench out of the way for now. Keeping the weight nice and light to start, hit 6-8 reps of Zercher squats and then re-rack the bar. Remove some weight (depending on how strong your squat and bench are respectively), bring the bench back over and hit 6-8 reps there. Finally, hit 6-8 reps of pull-ups with more assistance than you would usually use - these are all warm-up sets, so they shouldn’t be hard yet. Use how these sets felt to add some weight to the bar for each exercise - it still shouldn’t be super hard, but closer to being difficult sets - then repeat the same process. Use the first 5 minutes to get these warm-up sets done and to figure out what will be a sensible weight to use.
Finally, add weight to the point where 6-8 reps will be fairly challenging (you should feel like you could do 2-3 more when each set finishes - if you miss the mark, just adjust and remember for next time!). Set a timer for 20 minutes, and complete as many rounds of the above as you can whilst maintaining high quality reps - you should be looking at 45 seconds or so between exercises and potentially a longer rest of 1 minute-1 minute 30 after you finish a round. You’re not looking to work constantly here - you want high quality reps, so take enough rest and feel free to err on the side of this being a bit too easy initially. Make a note of how many reps and rounds you got done, alongside the weight, and you can either go heavier, aim for more reps or more rounds next time!
Enjoy!