Hello again,
I believe from the evidence of your experience that you are putting too much/misdirected effort into meditation. This could take the form of too focused concentration, rather than a balance between calming bodily and mental fabrications whilst developing awareness of the entire body as you breathe in and out; and/or suppression of thought. It's likely both if I had to guess.
Vipassana from the Goenka school teaches Anapana focusing on the nostrils. This is based in a common mistaken translation from Pali.
The mindfulness with breathing described in the Suttas is clear:
He trains himself, 'I will breathe in sensitive to the entire body.' He trains himself, 'I will breathe out sensitive to the entire body.' He trains himself, 'I will breathe in calming bodily fabrication.' He trains himself, 'I will breathe out calming bodily fabrication.'
Source:
Access to Insight, the Anapanasati Sutta
sensitive to the entire body and ..
calming bodily fabricationThese two phrases are key to understanding the beginning, middle and end of mindfulness with breathing practice: being 'sensitive to the entire body', letting the mind rest with the bodily sensations created by the process of breathing in and breathing out, engages and activates the vagus nerve and the parasympathetic or 'rest and digest' nervous system. When these are engaged and activated your body calms - especially when combined with the mindful intention to 'calm bodily fabrications'. When the body calms, the vagus nerve, which consists of around 90% fibres sending signals from the body to the brain says to the brain "hey, everything's good .. nothing to be stressed about" and the mind naturally begins to calm too.
Nowhere, in any Sutta is there a mention of nose-meditation.
The footnotes in the Sutta linked above does reference the Pali, Paramukham, "mindfulness to the fore" and possible interpretations, yet misses the correct one. This is best translated as "making mindfulness the foremost quality of mind" or "raising mindfulness" to be perhaps clearer: that is to say that one brings oneself knowingly to a state of mindfulness, one remains in this state, letting things be, letting thoughts arise, as they naturally will, and always returning mindfulness to breathing in/out sensitive to the entire body and calming the body, when noticing mind has attached to thought or to a train of thought.
So thought is not forced away ... practicing in this way one notices thoughts arising and falling, or one notices that the mind has attached to thought; moved away from whole-body awareness, and then with mindfulness is returned to the physical sensations created in the body by breathing in and out. This is done with compassion and kindness to yourself: no need to criticise that natural tendency of the mind to wander.
The point of the practice is to allow body and mind to relax, to calm, such that the tendency of mind to wander into thought dissolves naturally with repeated right-effort of maintaining a regular meditation practice. There is very little force used in this process: just enough to take mindfulness from attachment to thinking processes back to the body, again and again and again when it happens; always gently, without self-criticism, just remembering ("being mindful") that we do the practice not to get lost in thought, not to suppress thought, but to become a kind, gentle and accepting witness to the madness of our thinking and our identification with it. This is the only healthy and balanced way to allow thought to begin to diminish and eventually cease: to give it space to be, without identifying with it. "I am not my thoughts" is the most revelatory experience ...
I will propose an experiment to you. Take some days, or a week or so, away from meditating - enough time you are not suffering the negative side-effects you have described in your posts. Relax and forget everything you know about meditation. When you are ready use the "Calm Abiding" meditation notes from the homepage of the forum, and try this way of meditating for at least a couple of weeks .. a month is more useful.
Don't hesitate to ask if you have questions.