I get an adrenaline rush with anxiety - need some advice on how to prevent this?

Treat anxiety. To cut down on symptoms of anxiety, treat the anxiety. Start with a medical evaluation to check for health conditions which could predispose to anxiety or cause these symptoms. Psychiatric evaluation for further treatment, incl. Meds. Psychotherapy (cbt and/or psychodynamic, depending on your needs) can be very helpful. Also meditation & breathing exercises on your own. Avoid stimulants.