You are stressing.
Stressed is not a state-of-being. Stress does not magically happen to us. Stress is something we do. It is a controlled (albeit fairly subconscious) reaction that - yes - we can change.
Drop your shoulders, unclench your jaw, wiggle your fingers and toes, breath deeply, smile, maybe even laugh? Fake it at first! Then, eventually, take more walks, get fresh air, commune with nature, meet up with a friend, absorb yourself in a favorite hobby etc. etc
Most importantly, stop saying you're "stressed"!
