I'm sorry I hear this! I can certainly relate. Dealt with similar symptoms for a long time.
Has anyone ever mentioned to get your adrenals checked? It's something that most doctors won't even think about. I finally found a doctor that said it's the first thing that should be checked.
It's a blood test to check your cortisol levels, and if it's abnormal then it could indicate adrenal fatigue.
I am actually in the process of studying natural medicine so I have a few solutions for this.
In addition, this may sound crazy but I found completely cutting out gluten helped immensely! It took a few weeks to really notice a difference (as it stays in your system for a long time) but i was sleeping a lot better, and not having any panic attacks.
Other things you could try is stretching 30 min before bed, drinking herbal teas such as chamomile, marshmallow root, or licorice.
Hope this helps a little
Sometimes drugs poop out. When benzos poop out, called reaching tolerance, they can make anxiety much worse. People describing adrenaline surges really don't know that the adrenal gland is doing anything different, they just use the term and often incorrectly. If raising your dosages solves the problem, then they did probably poop out. Remember that if you're taking your benzo every day it is an addictive drug and that means that for some people they will need to keep taking more of it for it to keep working -- you take it to avoid withdrawal, not because it works better. This doesn't happen to everyone, but it's the same thing that causes heroin addicts to keep needing to take more to feel the same. Antidepressants can also stop working. But this could also be something physiological, and I'm a bit surprised your doctor didn't give you a thorough exam of things like your thyroid and a host of other things that can cause problems that sound like anxiety. This is one of the problems of using doctors for mental illness instead of psychiatrists and keeping your doctors for your other needs, which they are better at.
This sounds like increasing anxiety and panic to me. How long have you taken Lexapro and klonapin? I'm sorry this has happened. Have you begun increasing your antidepressant dose as your doctor instructed?