I recently picked up a copy of Lovingkindness: The Revolutionary Art of Happiness by Sharon Salzberg. I read up to the first exercise, and decided to give it a shot. I set a stopwatch and started up.

I've done a little practice with lovingkindness before, so I didn't expect anything spectacular. After about 8 minutes the feeling of lovingkindness was moderately strong. For whatever reason, I decided to concentrate on the feeling. Anytime I found myself distracted, I noticed the distraction with a more accepting attention. After about 30 seconds of noticing distractions with a loving attention, something changed and I felt my mind "grab on" to something (btw, perfect wording, Daniel). There was a profound sense of relief, and I felt a release of tension in my sub-navel chakra (tension I didn't know existed).

When I opened my eyes my stopwatch read only 12 minutes. I figured I couldn't let my newfound good mood and clear head go to waste, so I grabbed the candle next to me and decided to start concentrating. I've never tried candleflame meditation before, but I knew the basic idea. I concentrated on the flame until I had to blink, then I took the afterimage as my object. Initially, the afterimage appeared to be a ring of colors. Gradually, the colors faded and the black hole that was left moved into the center of my attention. Then, a pale red dot appeared in the center of the black hole. The dot became more clearly defined and started expanding. Finally, the dot began to bounce up and down. I thought, "Hmm.. is this why Indians have red dots on their foreheads?" And it stopped.

I have just a couple questions. Did I reach first jhana? And, I thought objects only move in second jhana. Am I wrong?

http://en.wikipedia.org/wiki/Afterimage

The weird visual stuff sounds just like visual after effects to me - I find sometimes if I shut my eyes and focus on the after image of a bright light it can do all sorts of weird and funny stuff.

Did you get rushes of excitement or tingles of pleasure? Or feel high?

Yes, after the sense of relief I felt quite blissful and happy. Almost mild euphoria, not quite high.

Always a tricky one, as people have different standards of what counts as jhana. And typically the feeling afterwards isn't the sign, as the point is the experience you have "in" the jhana (and what leads to it). If you are inexperienced you can be in the jhana for a very short period of time (seconds...) but with sklll you can learn to stabilise it and you will have a better sense of what is and what isn't jhana.

This is one the best guides I come across on getting to first jhana, and you can see how the descriptions match yours. :

http://www.leighb.com/jhana3.htm

The best answer you can get is to keep trying (if that is your goal) and see if you can replicate it. and explore that further. Though don't try too hard!

In that case, I probably entered first jhana for a few seconds.

What characterizes access concentration? How do I know if I've achieved it?

The instructions in the link I added in my last post gives a nice description.