Take deep breaths. Try to relax your tensed up muscles. Draw, perhaps simple shapes such as circles or squares, or triangles. Lying down sometimes helped me with panic attacks. Let yourself know that you will not be physically harmed in any way by the attack. Recognize the different stages, let yourself know you have gone through stage 1, 2, 3, knowing the end will be near. It's not the end of the world, and you will be healthy and happy once it is over. Focus your attention on one object, or one scent, or one sound. Listen to the sound over and over, as a continuous line that pulls you out of the panic.

Hope you are feeling better now.