Hi Michael,
I'm trying to give you a detailed answer to your first question. If you don't understand something, please feel free to ask. If you are interested in my opinion on the other questions please let me know.
In the following I want to describe, in my understanding of reality, what you may have experienced during and after the meditation. I write may here, because I'm not claiming to be a seer or psycic

. I just wanna make clear that all my following assumptions on your experiences are based on my own and could also contain some of my own misunterstandings. May the following words be of some benefit to you.
During meditation you were (as you described) focusing your attention on sounds and thoughts. At one moment (to another and maybe another, …) you felt a bodily sensation (intense pressure in your forehead).
At this moment(s) your attention got attracted by this bodily sensation and your focus shifted (away from sounds) to the pressure in your forehead.
So, this bodily sensation become your new object of meditation (knowingly or unknowingly, only you could tell). To this point it was only a sensation (without any positivity or negativity in it), it was just pressure, which you were recognizing.
Then your mind was reacting (unknowingly I assume) to this sensation, which showed up in a feeling tone (which in Buddhism is “only” to distinguish between liking, disliking and neutral). I assume it was a feeling of disliking.
This feeling of disliking led to identification with the pressure (=I’am the pressure) and a “judging” response (e.g. thoughts (knowingly or yet unknowingly to you) like I’don’t like it, make it go away, I should be calm, etc.). This thoughts probably caused a reaction of more bodily sensations, identifications, thoughts, which lead to more and more (unaware) confusion, till you came to the moment when you were recognizing: I’m anxious.
This bunch of bodily sensations, feelings, thoughts, etc. made up the story which we call anxiety. So, anxiety is not just one thing.
The really important thing were the moment you recognized anxiety: You were awake at that moment, being back in the here and now, experiencing some taste of anxiety.
So, what can you get out of that? The one side of your experience showed you, that this hole bunch of unknowing experiences (anxiety) were too heavy to handle for you and you was trapped in your anxiety instead of watching and observing it for what it really is (sensations, feelings, thoughts, etc.).
The other side of this experience motivated you to search for a solution/answer, to overcome your anxiety.
In short: Overcoming your anxiety with meditation is possible: You can do that in getting to know your anxiety better and befriend with it over time. Step by step, little by litte. Not forcing anything and trying to be gentle with you, even if anxiety overwhelmed you – it’s only human.
Meditation can be your training field, in which you can start to watch what your anxiety is made up of, it’s the playground in which you can get in contact with it. But I can’t say it often enough, don’t force yourself too much, start regularly but slow.
You may reflect on the following question:
- What do you think what meditation should be like/should not be like
- or in other words, does a good or a bad meditation exists and if so, what makes the good one
good and the bad one bad?
I also would be interested how if you tell me something about how you meditate (how long, how often, etc.)
Greetings Georg