I get these A LOT, the disturbing part is that it often happens during intense meditation, physical yoga and while very loaded, usually on cannabis but sometimes with psychedelics too. It's a very intense head rush that reminds me of the cannabis spins, but with a more pronounced "load" in the head, but with the same set of sensations, alteration of perception, vision tunneling to black, and complete or partial loss of consciousness. It is often triggered by lack of oxygen, quick movement, dehydration and certain movements of the body which effect spinal alignment. This state is also navigable, and with experience can laid to rest, amplified (not recommended) or altered depending on how one conducts themselves. I've found that it is often very psychedelic, though the turf is very strange indeed.
This seems to be not too uncommon, especially among the peculiar group of young, turned-on individuals who are compelled toward a point of efflorescence. In my experience it seems to be related to poor circulation, respiration and spinal health, specifically in the chest and neck. Relaxation both mentally and physically, good health and diet, etc help a lot.
If this is psychosomatic, embodiment of zen is the simple and obvious solution. In combination with good health, this removes the possibility of this drastic change in consciousness from taking hold by allowing the energy to flow through the body, rather than being trapped in the head. In this way, the sensation can be incredibly nice and imparts energy and vigor, a deeper perception of your relationship to the world, and a virtually impenetrable chill.
Either way, if you feel in any way that this is a danger to your health and well-being, then you should absolutely seek the help of a doctor or healer. I had a very nasty spill because of one of these head rushes, ended up whacking my head and ribs, and had a very brief seizure with a very confusing dream and time dilation experience. I can't imagine that it's good for one's brain, blood vessels or facial organs, either. Take care of yourself!
You probably should go see a Dr to figure out the underlying cause.
