Salu,
Good new regarding your health results! Take a moment to celebrate this...
...and then you can get busy and focused on the task of finding the right anxiety management program for you! :)
I think I would go back and talk with the psychiatrist again. This type of doctor is going to be the most knowledgeable in prescribing a psychotropic Rx that will best perform for your needs. Mirtazapine (a tetracylic A/D) and Xanax (a benzodiazepine) are very different Rx's, and getting guidance regarding which is the best choice for you is important.
He/she can also facilitate setting up therapy for you, which I believe is necessary for the best and well rounded plan of recovery!
For now, please take advantage of our great self help material in our Resources. (see link below) Spending just 10 or so minutes a couple of times on day on the suggested exercises can start to make a big difference!
https://www.healingwell.com/community/default.aspx?f=9&m=104206
Keep posting with us as well. We care and support is key!
Talk soon,
S.C.