Try this, everytime you feel one coming on.

Breathe in through your nose for one second quickly then pause then breathe in again through your nose all the way down to the bottom of your lungs then as soon as it feels full push it straight out and then enjoy the silence then repeat.

Eventually the silence at the end when your not breathing will last longer and you will be able to get to deep levels of relaxation quickly in times of stress. if you want any more info from a fellow suviver let me know lol

It's a Yogi breathing technique does wonders before interviews train trips etc etc

good for PA's too, I got given ciprilex escitalipram for mine had it got rid of them.

20mg a day from 5mg up gradually no side effects either