A few thoughts that might help:
While your particular problems are unique, the wrenching thought patterns you experience are not. You are not alone, your problem is well studied, you can be treated, you will get better.
I don't want to minimize your problems because I know they are important to you. But a huge part of your current anxiety is caused by your fear of your anxiety. You feel a twinge of anxiety, then dread, your mind kicks into overdrive (even if you were finally, at last, just about to fall asleep!), those terrifying thoughts rush up on you, you battle the inner voice in your head, solutions to your problems either never appear or quickly turn to sand, slipping from your grasp, and those thoughts go around and around, all the while making your anxiety worse. This is not inevitable. You will learn not to fear that first twinge of anxiety when it comes. That feeling is just that — a feeling. It cannot hurt you. Your awful fear of it is what causes your mind to race in search of its cause, and in doing so your mind dredges up all of your life's most difficult problems. Then you brood over them to no end for hours — instead of getting better, you get worse. Things will become so much easier when you learn not to fear that first feeling of anxiety. Just experience it. It will pass, like all other sudden jolts of emotion, when you no longer fear it. It will simply melt away instead of turning into hours of agony.
You will also learn to stop those horrible thoughts from spiraling out of control. Once your mind starts racing, I'm sure you sometimes feel like you're going crazy. If I can't control the voice in my head, what else is there? I'll become a mad man. You are not going to go crazy. You just won't, I swear. And here's why: you are not the voice that prattles around in your head. Those are just thoughts. They come and they go. You are the person who listens to those thoughts, and you can liberate yourself from them and the terrible effect they are having on you by gaining some control over them. You can learn to simply observe those terrible thoughts when they emerge, and to let them float away.
Once you see that feelings of anxiety are nothing to fear, and once you learn to let those awful thoughts float away instead of battling them, hopelessly, for hours on end, you will feel liberated.
Right now, you are emotionally drained. The slightest stresses or surprises might cause your anxiety to erupt and those thoughts to start racing. A slight feeling of sadness might swell into a wave of depression. This is all normal. Do not feel that all is lost every time you take a step back. You will get better, even if on your march forward there is an occasional step back.
You might think you are weak, but you are not. You have been living with awful fear for weeks. It is unimaginable to those who have never felt it. And yet you're still here, having gone through so much. One day you will realize you have seen fear at its worst, you have come through it, you have learned to control it, and you will feel an amazing strength.
I highly recommend that you download Hope and Help for your Nerves by Claire Weekes and Mindfulness: An Eight Week Plan for Finding Peace in a Frantic World by Mark Williams and Danny Penman on your iPhone or Kindle or whatever you've got.