Diet - food - can have a huge impact on stress. Ensure your getting all the essential nutrients, eliminate sugar, and reduce carbohydrates (go full keto if you can). See metabolic mind for the emerging research on the food brain connection especially with respect to anxiety

Sleep - not getting enough sleep increases cortisol and stress hormones all day

Inflammation - if your slightly allergic to something, like low grade celiac, but eat it anyway... Inflammation, and stress hormone response