First and foremost, you MUST realize this anxiety attack for what it is when you are having one. Understand that you are having an anxiety attack, and that it won't last forever. Most attacks only last anywhere from a few minutes up to no longer than a half an hour. Give or take.
Even though it may be difficult, try to lay down and RELAX.If you can't lay down, sit still, close your eyes and focus on slow, even, breathing. This will help ease the symptoms somewhat. Not completely mind you, but enough that you can make it through.
The REAL trick in battling anxiety is to redirect your train of thought. Keep yourself as busy as you can and let the thoughts of fear of an oncoming attack melt away. They will. And the more you practice this reversal of thought, the better you will get at it and be able to manage your anxiety attack better the next time you feel one coming on.
If it becomes too much to manage on your own, seek medical assistance quickly.Never feel embarrassed for having to call an emergency squad. That's their job! These courageous folks get calls like this all the time, so you should not feel the least bit of embarrassment or guilt in asking for their help.