For me, the first thing is catching up with colleagues. Not just about work but just spending some time to talk about life.
After that, do some work of course :)
I would have an eve planning what is going to happen next days, and calm morning routine next day will make me calmer at least :)
Fan of calm Monday mornings, so need to wake up like 5-6am
Before we started working on Sense (https://senseapp.ai) we did some Customer Development. And this was the exactly one of the questions we asked our responders. 100% of them replied the same thing: I'll call a meeting to update myself of what happened during my absence.
People keep paying tons of money for tracking tools and task managers, but they still need to bother other people, because there is still no place where they can get some meaningful insights from all their team resources and processes.
This is what we want to fix at Sense.
Stooa