Sorry you went thru a bad panic attack - no fun for sure. I learned diaphragmatic breathing (belly breathing), that I practiced all the time, which helped greatly . When I would start with an attack, I would QUICKLY check my breathing - and it was usually not right - and kick in the diaphragmatic breathing. That should help u alot. Also, use guided imagery, or visualization - quickly think of a place that is peaceful and calming to you. Try and relax your body quickly. TELL yourself, this is only a panic attack, it will pass, I have had them before. If you havent read self help books on panic disorder, I think the best one is Anxities, Phobias and Panic - Taking Charge and Conquering Fear by Reneau Z. Peurifoy (he is from CA !) I used that book as a text book while facilitating a Support Group for people with panic disorder for 7 years.

Good luck, and welcome to the site !