How can I stop panicking again when I face the triggers again?

You can stop panicking when you feel the triggers again by remembering the trigger will go away in a (hopefully) short amount of time. Talk about it with a close friend, they will be the most help.

You don't have to panic. Wear a rubber band around your wrist and snap it when you are panicking to overcome panicking and this helps me a lot to snap out of it, I think it will help you too

By engaging in deep breathing, taking a deep breath in through the nose for 5 seconds, holding it for 3 seconds, and letting it out very slowly through the mouth for 8 seconds. You should feel your body relaxing and releasing tension when you breathe out. Continue deep breathing!

Slowly start facing up to the triggers little by little - at least those you know you cannot get away from.

Good thing is that you already have a knowledge of your triggers and can use this to your advantages by planning ahead... I like to always keep a journal or a small notebook with me where I can record emotions and triggers. I spend 30 min at the end of the day going through my notes and mentally rehearse or plan for my future actions in case I will have to face the same situations again. If it happens, I notice that my reactions usually improve over time.

while I was still getting triggers from ptsd, I found that avoiding situations or places that would set off a trigger. As time passed and some triggers are unavoidable, it got easier and easier for me. It also helped talking to people about them and why it set me off.

I know this is cliche, but just talk to yourself in your head. Tell yourself it's okay, you're okay, count if that helps, or sing your favorite song, remember a quote that motivates you! Anything that brings you positive feelings, use it. Whenever I feel triggered I start talking in my head, cutting off any negative thought or feeling I may have and replacing it with positive thoughts/feelings. Remember to breathe, prioritize your thoughts from most important to least. Don't think about the could've, should've, would've, just accept what HAS. Don't try to fight any emotions you're feeling, let them visit but don't let them stay. Acknowledge you're feelings, and allow them to pass.