Panic Attacks Support Group
A panic attack is a period of intense fear or discomfort, typically with an abrupt onset and usually lasting no more than thirty minutes. Symptoms include trembling, shortness of breath, heart palpitations, sweating, nausea, dizziness, hyperventilation, and sensations of choking or smothering. Panic attacks can be very sudden, appear to be unprovoked, and are often...

Also, I'm not sure if this will help but sometimes when I feel an attack coming on I find something to count. I know it sounds silly and may not completely stop your attack but I find that sometimes it helps alleviate it. I'll look for a certain color and try to count as many of them as possible.
Good luck,
Maria