One important thing to remember is that there are no "classic" anxiety symptoms. Everybody's different and everybody reacts to anxiousness and stress in different ways too. While there are certainly some common symptoms that many people have with anxiety attacks, there's no right or wrong way to have one and there's no one path that it takes.
Anxiety attacks play on the body's fears and the body's intentions. It revs the body up, trying to get things moving so that it can help combat whatever you think you're "afraid of." It's a fight or flight response gone extreme, basically, and the best way out is to stop running and stop fighting. It's hard to do because it's against your very nature, but it's important to remind yourself that your symptoms are healthy and normal when the body is trying to bail itself out of what it perceives as trouble.
You're not crazy, you're not having a heart attack, and you're not dead yet. Remember that anxiety is helpful and that it, in right circumstances, can save your life by moving blood and energy around where it is needed.
Your throat more than likely closes up to give your body more control over oxygen intake, thus delivering the right stuff to the right places as needed. Try to remain calm and don't gulp air (that's why yawning is). Instead, try to breathe slowly through your nose as much as you can and hold that breath for about four or five seconds. Release it slowly. Rinse. Wash. Repeat.
Most importantly of all: try to remain calm. You aren't going to die or run out of oxygen or faint. It's part of the body's normal reaction to the stresses it thinks it's enduring. Keep cool and everything will come up aces.