I'm so sorry that you feel terrible. I agree, everyone needs a little help now and then! There's nothing wrong with how you're experiencing this. There may not be a simple answer, but you will be ok. When you have more minor-level panic attacks, are you able to use any grounding techniques? I shared 54321 grounding on the thread above:
Name five things you can see in the room with you.
Name four things you can feel.
Name three things you can hear right now.
Name two things you can smell right now.
Name one good thing about yourself.

I know that this won't help with many panic attacks or with POTS, but it may help when you're expereincing anxity about the holiday or other things, to try to keep you otherwise relaxed.