You need to bond, then everything feels a little easier. I'd take about half of his daily food out into a treat bag, do a lot of recall house/garden/walks. A lot of At heal walking and whatever other behaviour you'd like to see, reward, reward, reward.
can you pin down what exactly is overwhelming you? You might be able to put some things in place that reduce your stress?
i dog sit my friends lab a LOT at their house. He's gorgeous, but creates mess & chaos everywhere And I was forever hoovering, mopping, picking up chunks of destroyed toys. So now when I arrive I remove a few of the toys he has mostly shredded (and just leave a trail of filling/bits of 'string' everywhere) move a mat from the unused side door to put beside the one at the large first door of the bifold, put his water dish on a mat, and shut the lounge door.
all of this makes it much less work day to day (hour to hour).
Teach him a morning routine that works for his NEEDS, but with as much of your wants as possible. Big Lad gets taken outside for a wee (waits until you go out with him, won't go out alone) & a dental stick. Then settles down for a bit while I have a coffee, I've taught him nothing fun happens until I've had coffee.
we then go for a sniffy walk & when home play in the garden. He then settles down with a big biscuit while I have a shower etc & another coffee.
For me, that's the key. Meeting their NEEDS, but considering your own too in how that happens.
He knows we all have different routines, but that he still gets everything he needs xx