You have to learn how to turn it off by not worrying about things you cannot control and taking action on things you can control.
I've worked as an Engineering Consultant for 15+ years. It gets stressful working on large complex projects all the time. Many times i'm hired to find flaws in a design or find a way to engineer it cheaper. This can be hard on me.
Years ago i had serious anxiety issues. Today i've learned to let go of things i cannot control and just focus on doing things i can control, do the best you can on what you have control over. When you are always ahead of the game, you feel better and rarely feel like you left something behind.
If that doesn't work. Drugs.