transcendental meditation question

[pondini]

i've used my own form of meditation to relax in preperation to attempt AP, but the other night i tried a new method i read in My Big TOE. it uses a mantra consisting of a string of non-meaningful words that end in a soothing sound. i used the example from the book:

ah lum bar dee dum, ah lum baa dee dum...

i repeated this sequence, only hearing the sound of the words and gently pushing out all other thoughts. immediately i thought this was going to be the longest 20 minutes of my life. that wasn't the case. after ten or so minutes i felt something happening in my mind, maybe like my consciousness was moving towards the sound -strange when you consider that both are supposed to be in my head to begin with. ok, so i was surprised that anything at all would happen during my first go at it. so far so good, but that's not why i'm posting.

next, i felt a growing pressure on my chest, it felt like the description of a panic attack, and my chest, neck and shoulders felt like i was having a severe hot flash. i knew it wasn't a coincidence and remembered that the author had written that the ego fights back in strange ways when it thinks it's in jeopardy. with that, i committed to ride it out, knowing i was in no danger. had i not remembered that mention of the ego and its little tricks i would have ceased ASAP, as it felt like a heart attack or like i'd been poisoned. to be honest, even after my commitment to push through, i damn near aborted. it was that uncomfortable. a few moments later the discomfort dissipated and i was back 'in' the sound of the words, just as my brother created some racket at my end of the house.

at this point it was 11:30 so i decided to crash. with the lights out i started right into the mantra. i was back into the sound after about 15 minutes, when the exterior sounds of my room began to fade in and out at a ratio of about 2/1 seconds per interval (2 seconds of normal hearing / 1 second muffled). i also sensed some pressure in my head during this time. i've experienced this same effect a few other times while coming out of lucid dreams, an AP, and once while meditating in preparation to AP. i have a simple theory on it but i am interested in hearing from others with more experience, as well as knowing if my physical discomfort is a common occurrence.

i thank you all for reading and i appreciate any insight provided:)