You may have some viral and/or bacterial infections and toxicity going on.
I wish we had easy access to dark field microcopes in this country. It's wasn't a pretty site when it came to bacterial infections, but after a few months of antimicrobials, my blood looks pretty clear. I had bacteria (mostly L forms) taking over not only my red blood cells, but also white blood cells.
Treating Lyme Disease and toxicity has lessened these symptoms for me. Don't get me wrong, the anxiety is not all better, but I used to not be able to ride in a car without freaking out. Now it's not a problem. Treatment made me feel generally worse for a long while (herxheimer reactions), but the indescribable anxiety and fear is a lot better and now I only herx about once a month. Oh, and I used to dial 911. And no, I was never crazy, just very ill. I never dialed 911 in my life, and the times I did I felt my life was at risk. I still have anxiety (though I prefer terms like toxic encephalopathy because that's what it is). I had viral gastroenteritis a few days ago (it hit my brain really hard and raised my anxiety 10-fold) and I ended up in the ER because of the after effects. They thought I had a heart infection called pericarditis, but it seems that I don't thank god.
Have you ever been treated for bacterial infections (often opportunistic)? It probably won't be a cure, but it may help you.
And based on personal experience, it sounds like you aren't detoxing. I can't tell you what detox protocol you need to be on, but I can tell you that your ability to detox and your level of anxiety can go hand-in-hand.
You should seek medical treatment. You obviously need it. You may not get better, but symptoms can be helped. Though I don't believe allopathic/modern medicine approach could do much to make you feel much better. Maybe a sedative/tranquilizer could help, but those are addictive. I am not against them, as I take them myself. Maybe you are already on them.
An N.D. in combination with Integative Medicine doctor with an understanding of chronic disease states and CFIDS/ME may be a good approach.
Finding competent practicioners is the hard part. Best of luck.