I don’t bite off more than I can chew, for starters.
When life gets a little nutty I pace myself. Start work early, do a little every day, finish before the due date without having to scramble.
Most of what I put into my schedule is stuff I want to be doing. I’m busy, but I’m not unhappy. The busy-ness in and of itself can make me a little frantic but I’m learning to reel that in and realize that just because I’m rushing from place to place doesn’t mean I need to feel anxious.
Decide on a few essential daily “me-time” activities and don’t deny yourself them, no matter how busy you are. For example, I will never even think about work during breakfast. I might do work while I eat lunch or dinner, but breakfast is my gearing up time. I don’t think about work for at least 1 hour before bed, usually more. I give myself 8 hours for sleeping.
Working out is a great way to burn off the jitters.
Take a walk. It’s amazing what fresh air and attention to your surroundings can do for you.