When you're experiencing an attack, make sure you sit down, put your head between your legs and breath deeply!
Make sure you can feel your belly expanding when you inhale, focus on that. Close your eyes.
It used to help me to speak out load, tell myself: "It's going to pass, it's going to pass, it's going to pass."
And then it does. As I've learned to control it, I find myself experiencing it rarer and rarer.
I hope this is going to help. You're going to be all right, just you remember that. (:
Progress is slow, but be patient.
If you don't find it to be improving, try speaking to your doctor. He/she might have some tips.