I have been meditiating for many years, it is just a euphamism for self hypnosis with religious connotations thrown in for good measure, it can allow you to acess your subconcious mind and that is likely what happened to you. However randomy acessing your subconcious, without intent or control is likely to just throw up random "Visions" as you call them without purpose.
Use visualisations to learn to control this and you can very quickly get to the bottom of emotional problems and those odd feelings psychics are so quick to attribute to supernatural phenomena but which are infact perfectly normal attempts by the brain to put life in order.

All I know is I am having a second cup of coffee every morning.

I Have Heard Of People Having Similar Experiences.They Have All Involved Some Sort Of Constant Beat,Or Recurring Tone.Maybe Some Sort Of Induced Trance?

Every time I tried group meditation it was boring because I can't concentrate with people around me like that. I can meditate alone though, but I am a true introvert.

I’ve meditated off and on for years, first under the guidance of a Zen Buddhist teacher. I’ve experienced the sensation of rising up and floating. Once I found I was able to control very innocuous hallucinations. Spooked me because I enjoyed them.

I’ve meditated off and on for years, first under the guidance of a Zen Buddhist teacher. I’ve experienced the sensation of rising up and floating. Once I found I was able to control very innocuous hallucinations. Spooked me because I enjoyed them.

Maybe not as intense as what you're describing, but a long time ago I was doing meditation with others to recording of a Japanese flute (Bell Ringing in an Empty Sky, which I now have the cd of), and I had an experience that played out in my head like a movie. I was traveling on a road going up and up into the mountains, to where there was permanent snow. Then I turned off and started downward into a steep valley, though still very high up. At the bottom of the valley a stream was coming out of a cave in the side of the mountain. I waded into the cave and was looking around, when I noticed a light coming from a small nook. When I looked inside, there was a shaman-type person sitting by a fire with his eyes closed. His dress was elaborate, though not specific to any culture I recognized. He opened his eyes, looked at me, and started laughing. This seemed very profound to me at the time, though I'm still not quite sure what it means.

even a great atheist once said, everyone believes in something, especially when you're sick or about to die.