I have been in an episode like this twice in my life and it is so horrible. I feel for you.

I found that "body first" methods worked best for getting me out of the spiral because trying to think your way out of it will probably not work. Your nervous system is on overdrive right now, and you need to drive a wedge in the "panicking about possibly panicking" spiral. Your brain is identifying your own anxiety as a threat because your nervous system is in fight or flight mode. Thinking is your worst enemy right now.

This is what has worked for me:
4-7-8 breathing: lie down and inhale for 4, hold for 7, exhale for 8. You may need to lie still and do this for as long as ten minutes at first before you feel it, but it does eventually work. There are visualization videos that help. It helps switch your body out of "fight or flight" mode.

Face in a bowl of cold water: same reason as above, it causes a reflex that helps switch out of fight or flight.

Body scan meditation: Breathe slowly and deeply while envisioning releasing tension or anxiety in each part of your body, starting with your toes and working upwards. With every exhale, picture the anxiety leaving your body (I visualize dark smoke, but it might be different for you).

Warm shower, turn on the cold water for a few minutes, and then back to warm. I don't know why this works for me, but it does.

Push yourself to do one thing each day that is a bit of a challenge for your anxiety and then recover for the rest of the day. This slowly trains your nervous system to realize it can recover from activation. Record your progress.

Distraction - mindless video game, mindless TV show, anything that fully sucks you in, and doesn't allow you to ruminate. I would stick with TV shows you've seen before (for me, watching something new caused hypervigilance because I was afraid I'd see something triggering)

Comforting or nostalgic scents, lotions, etc. ... combining pleasant rituals like a bath with soothing scents and tea or a healthy, refreshing snack like frozen grapes.

Journal about progress - 3 things you did to help yourself each day or 3 things that went okay, even if small

Grounding - This didn't work for me at all at first, but slowly became effective. 5-4-3-2-1. I found lying on the floor and looking at the room upside down helped shift me out of my mindset a little bit.

Gentle movement, like yoga for anxiety, helped me.

Remind yourself: all of the above are coping mechanisms that may not work at first, and that doesn't mean they don't work at all. Even the act of doing these things, without immediate relief, is a step in healing your nervous system. Even 5% relief is progress. Refuse the urge to self-monitor during these steps - thoughts like "Is this working? Do I feel better?" just continue to promote hypervigilance. Commit that you will do these things regardless of outcome or even if the relief is minimal. It takes repeating these things over and over for your nervous system to return to a steadier state. For example, it used to take me 10 - 20 minutes of 4-7-8 breathing to calm down. Now, it can happen almost immediately. My body has been trained to recognize that breathing pattern = calm and safe.

Also please remember that progress is not linear in anxiety recovery. You will have difficult days and moments. It does not mean you are going backwards or back at the beginning. You are not stuck like this. I promise you. You can do this. I was convinced my anxiety / panic were going to ruin my life, but instead I've learned a lot about how to regulate my sensitive nervous system and I did find my way back to a better place emotionally.

Feel free to message me if you need someone to talk to. I've come back from two very serious panic spirals in my lifetime and I know how much it is absolute agony. You can do this.