Trauma disrupts sleep almost universally, and lost sleep makes everything else harder to carry. It is the highest-yield single lever available to you. Food and movement are close behind — not as self-improvement, but as the floor everything else stands on.
Go to bed and get up at the same times, even badly. Same times matter more than enough hours, at first.
Eat something regularly. Blood sugar and mood are not separate systems, and skipping meals makes tomorrow harder in a way that has nothing to do with willpower.
A walk. Not a programme. Movement discharges stress chemistry that talking cannot reach.
A longer out-breath than in-breath, for one minute.
Five things you can see, four you can hear, three you can touch. Have this ready before you need it.