Panic attacks are not just in your mind, they have a physical cause, adrenilin.
When you are in a situation you are uncomfortable with, you just want to get away, so your body floods you with adrenilin.
This is when the physical symptoms occur. Jelly legs, shaking, heart racing, hyperventilating etc.
Adrenilin is released in this way for us to get away from danger. You either fight or flee.
The amount of adrenelin the body can release at any one time is limited. So when the symtoms occur, they have to subside because after a short time there will be none left, and the body cant release more until it has replenished its supply.
What you have to learn is that panic attacks are not dangerous, nothing bad will happen to you. All it is, is the fear of them happening that will actually cause the adrenilin rush.
When it next happens, wherever you are, just stop and wait for it to pass. Which it will. It has to. The amount of adrenilin in your body is limited.
If you are out, sit on a bench. No bench, then pretend you are looking in a shop window.
If you are in a supermarket, hold onto the trolley and pretend to study the labels.
No one will notice you. You will not be ill from any of the symptoms no matter how bad they are.
It will take quite a while before you start to feel and understand that you just have to let the panic attack pass, and dont fight it.
I can recommend the books by Dr Claire Weekes, which are available on Amazon.
You have lots of time before you have your wedding next year.
Good luck