In the movies, there is usually a "good guy" and a "bad guy". Usually the good guy starts off appearing really strong. Then as the plot progresses, the bad guy increases in strength until the point comes where he seems utterly invincible. But in the end, that strength is always revealed to be nothing but a house of cards. The fight may be epic, but the good guy always wins. Usually the seemingly strong foe has a simple weakness that the good guy able to exploit rather easily once he figures it out. This is a lot like anxiety.
It shouldn't be a surprise that the bad guy in this analogy is anxiety, and the good guy is you, the person struggling with anxiety. Anxiety usually comes on small, with just a little nervousness that can be easily dismissed as nothing to worry about. With time, though, it increases in it's intensity until it engulfs your life and your situation seems absolutely hopeless. The important thing to realize is that you are the good guy, and the good guy always wins in the end. The strength that you possess may not seem like a lot, but you have one major thing going for you. Your strength is real. It is grounded within you and cannot be taken away.
The strength of your anxiety or panic may seem overwhelming. But it's not real. It's a house of cards that be blown away with the same breath that you'd use to blow out birthday candles on a cake. It's not real because anxiety has no real power. It relies 100% on YOUR power to fuel it's attacks. Anxiety comes totally from within. It's your brain, and your mind, and your body that are being used against you to cause you to panic. Once you realize this and you see the anxiety for the house of cards that it really is, all you have to do is blow and you'll watch it fall.
It's a lot like Judo. Judo is a form of martial arts that focuses on using an opponents strength against them. You don't have to be strong to practice judo. Instead, you simply rely on the strength of your opponent. You just have to predict how your opponent is going to use their strength and divert it so that their own strength is used against them. This is what anxiety and panic are doing to you. They have no real strength of their own, so they trick you into using the considerable strength that you have on yourself. The harder you try to fight your panic, the more the panic wins and the worse your panic attack becomes. The winning strategy is to not play into what anxiety is leading you to do. It's predicting your attack, and it's waiting and ready to knock you on your back. All you have to do is what it does not expect: accept it. It will have no counter for this. This is much like instead of attacking when it is goading you, just put down your weapons and stand there. Realize that it is unable to attack you on it's own, because it lacks strength. If you stand there and wait, it will go away.
If you are distressed by anything external, the pain is not due to the thing itself but to your own estimate of it; and this you have the power to revoke at any moment.
-Marcus Aelius Aurelius