I have long periods of depression and anxiety.
I've had them together for so long, I don't know if it was ever different.
Meds can help, and doing a lot of research into learning more about it. That helps knowing I'm not the only one who experiences these things.
Getting a professional to help you recognize when you're brain is being a bad tool, and knowing how to get a handle on the tidal wave of feelings.
My coping includes simplfying as much as possible, making specific dates to keep getting the stuff done that gives me anxiety later because of worry, such as working on my budget and reviewing banking, and boring stuff like that. Just 3 days over the course of the month, I get a lot done, and can tell myself I don't need to worry, I did it already.
I've found that I really am better off being as free of other people's drama as possible is helping. I have limited my exposure to toxic bs that helps a lot.
You need some help with understanding what's going on with you tho.
Until you can get to a professional, doctor, or whoever you see, try to take it easy. Drink calming tea, keep your surroundings quieter, listen to soothing music, find things to take your mind off of spiraling down that rabbit hole.
It does sound like you have a bit of a panic attack thing going on, it's not something you just tell yourself not to do, it's a difficult experience. I'm sorry for the hard time you're having now.
It will get better, in it's own way. You'll have better days ahead of you.