I have minor panic attacks or can be simply qualify as a human worrier. It is human to worry and slip every once in a while to think of incidents that never happened and yet scare me when it actually do. My solution is to go back to the calm.
I may have said it a milion times here, in Quora, or even to my friends but going to a relaxed mental state helps.
Breathing and watching it when you do it is a start. Be conscious while you breathe in and out and then let go of everything that is worrying me. Relax by shaking my shoulders and continue to breathe in and out slowly, not hurrying. Smiling helps too knowing that right now I could find peace and forget everything that is bothering me. If a nagging voice arises, smile even more, and then tell it to stay quiet.
How do you calm down?