You just have to ride it out I suppose, obviously try doing something to keep your body busy, go for a walk or do some simple and repetitive task that will keep you totally absorbed and physically engaged in what you're doing.

Today I felt this way somewhat, I went ice skating on a pond for a while and felt better.

Or, find someone who loves you and tell them you need a good hug

My first real anxiety attack was scary, I didn't know what was happening to me or what to do, eventually I talked to my dad for a while (though I didn't know what to say exactly). He calmed me down and held my hand, it was kinda weird but it worked. People definitely understand these things and can help you if they've been through it before.