I don't want to be rude because you are being helpful, but mindfulness is not the answer to everything. Mindfulness made me even more anxious because what I really needed was to see a psychologist.
Just to provide an additional data point, I've sought relief from anxiety in meditation, failed, and then found great relief in cognitive-behavioral therapy. You're exactly right in that what's needed sometimes is conventional help from psychologists.
A few years ago, I delved again into meditation, this time more traditional Buddhist ones. I can't say emphatically enough that there is some deep knowledge there. Mindfulness (i.e. cultivating stable attention toward internal & external stimuli) is just the tip of the iceberg.
Like you, I found the expanded sensory stream provided by mindfulness training to be somewhat overwhelming. Imho, what's necessary to work with it fruitfully are: 1) developing the capacity of non-abiding, or not attaching/identifying too much with the flow of mental events, 2) training the unconscious mind to competently manage one's attention & awareness, so that you don't have constantly "pilot" your self.
Two books I've found indispensable are:
The Mind Illuminated - John Yates, and
The Rinzai Zen Way - Meido Moore
Of course, there's no substitute for a good teacher. Just be aware that there are many charlatans & New Age types who aren't so helpful. Good luck!
Agree it's not a silver bullet, especially when someone needs actual medical help. But mindfulness can certainly help break the cycle of self perpetuating stress.
My experience with lay practitioners (such as myself) is that you may have to try a few different things to find something that works while living a regular life. The Mind Illuminated, the Sedona Method, Louise Hay, the work of the stoics, yoga, qigong, therapy, all provide different approaches to developing emotional intelligence and managing difficult states of mind. I did zen meditation for a decade and while it provided many benefits I still struggled with anger in my day to day life. Two months of reading about and applying the stoic principles completely changed that.
It's not going to solve all of your problems. But I know it's possible to be so anxious that you can't even bring yourself to get other forms of help you need. And in other cases, it can help break the vicious cycle you described.
Learning to slow down and breathe are the simplest thing that many never learn.