The situation A gives rise to the thoughts B causes the anxiety C, the anxiety makes the situation seem worse leading to further thoughts leading to increasing anxiety, and so on and so on.
Symptoms are a result of adrenaline, a totally natural response to a fight or flight situation.
Heart rate increases
Feelings of dizziness
Shortness of breath through tension
Legs feeling heavy/ weak
Confusion
Good news:
Adrenaline is metabolised in the body in approximately three minutes.
If an anxiety attack does occur you have the ability to overcome it quickly maybe even before physical symptoms appear.
Change your thought pattern, practise, practise, practise