Well, I had to look up a few of those terms... jhana for instance.. because I have had no formal training, and am only now starting to thrash around in the literature.
Perhaps I should also mention that as a long term taijiquan practitioner I am fairly comfortable with energy work, and I also indulge in a practice called zhang zhuang (standing like a tree) using 'Sung' breathing in which the breath is centred on the dan tian area and all the joints and non-postural muscles are allowed to relax into their natural positions. This is the breathing I utilise when I sit and meditate.
Unfortunately there are no theravadin teachers anywhere near me, so no luck there.
On the up side though, I feel no particular desire associated with the experience: it was just what it was, in effect. If it happens again then fine, if not then so be it. I just thought it was a curious thing.
Thanks for all the input. I'm learning as I go.
If I may add, I am not following any particular path - which may or may not be a problem in itself. As it is I have a bit of a mix and match approach. When sitting I alternate breath watching or mala/mantra (not in the same session though). My only texts are: The Diamond the Cuts through Illusion (TNH), The Heart of the Buddha's Teaching (TNH), The Heart of Understanding (TNH), Finding Our True Home (TNH), Lessons from the Lotus Sutra (TNH), The Zen Teachings of Huang Po, Treasury of the True Dharma Eye - by Dogen (in PDF), Peace is Every Step (TNH), and Zen Keys (TNH). As you can see I am a bit of a fan of Thich Nhat Hanh!
When I visit my home temple (Longhua, Shanghai) I tend to be drawn to Sakyamuni, and Guanyin. In the last few years (especially stemming from a bitter divorce 6 years ago) I have found it increasingly difficult to be angry or irritated with people - a kind of watered down version of tonglen perhaps. I certainly feel quite kindly toward pretty much everybody, although it is disappointing how many people take advantage of that.
Anyway, I find all the buddhist practices to be interesting, but I am put off by any that smack of overt institutionalism such as is displayed by (for instance) the Catholic church. Ritual is fine as long as there is no overtone of clerical control.
I am a bad practitioner I suspect.