Breathe.
You are going to be okay.
Breathe and remember that you've been in this place before. You've been this anxious and scared... and YOU'VE SURVIVED.
Breathe and know that you can survive this too. These feeling can't break you.
They're painful and debilitating, but you can sit with them and eventually... they WILL pass.
Maybe not immediately, but sometimes soon, they are going to fade, and when they do, you'll look back at this moment and laugh for having doubted your resilience. I know it feels unbearable right now, but keep breathing, again and again. THIS WILL PASS.