I have my work email notifications turned off on my phone.
I have a “work stuff” folder on my to-do list app so if I think of something I can quickly add it so I won’t forget and won’t continue to think about it.
I have written to-do lists that I check off as I complete them at work. Whenever things start to get overwhelming it helps to break them down into manageable tasks and focus on what I can complete in the time I have.
Occasionally a moment gets too much (usually after a day off and we have an early meeting, something that throws off my routine). I give myself my moment locked in my office and then continue with my day. Taking a few minutes helps me recenter.