Hello Lionheart. I know this is an old thread. I hope you have found relief.
Like many of the folks here, I have quite a story when it comes to meds. Basically, over time, I have tried just about every class of psych meds (aside from antipsychotics) and most every drug in every class...to little or no avail. Much of the time the meds have only made things worth.
With that in mind and noting that everyone responds to meds differently, there are a couple thoughts I would share.
Mirtazapine has helped some with depression and anxiety, but mostly just with sleep. Nothing works as well for me for sleep as Mirtazipine.
Clonazepam helped me go from "life is absolutely unbearable" to "OK, I can at least tolerate life at home, by my myself". It never got me to a place of even close to full functioning. In the long run, the price I paid for taking Clonazepam was not worth the benefit.
Benzodiazapines are horrible drugs. Horrible. Probably the most addictive drugs in the world. Not addictive like, oh, I've just got to have some more of that stuff. Horrible like, when I cut down slowly, even 5% per week or two, I feel like living death most every moment of every day. The withdrawals are actually 10x worse than the underlying anxiety. And they last for months or years. In hindsight, I would never have taken a single benzo if I knew the price that comes with them. For many folks, staying on benzos long term means dementia and even worse anxiety that cannot be treated by anything in the long run.
Lithium is not typically prescribed for anxiety necessarily. But if your anxiety is a comorbidity, then it may be helpful. My only experience is with the supplement form in very low doses. It has been somewhat helpful. The prescribed form in higher doses may be similarly or more helpful.
There are some other substances which can be helpful for some folks. Some minerals and supplements. Some substances, discussion of which belongs in another topic.
In my case, I've had to come to be resigned to being disabled by anxiety. (c-PTSD, MDD, GAD, Social Anxiety Disorder, etc.) I have found that time and being easier on my self has helped some. Beyond that, my case appears to be pretty much "refractory."
I hope for better things for you!
Woodsy