often - i get a headrush - almost blacking out
the way i handle it is to drop the height of my head and breath heavily
its the oddest trip ever - leaves me with an odd expression on my face
long ago i failed at stopping it and i think i had like a seizure and stopped breathing for 3 mins - freaked aegle out
actually i think its happend 3 times in total
often i get a major realization - that i have to struggle to hold onto - to bring back into this realm.

i had brainscans, blood tests, and many other tests and all say im as strong as a mule - so idk or really care i just accept it as part of life - i even enjoy it.
anyone else have this happen to them on a regular basis ?

I can get this from cannabis sometimes.

Though when I was a child this would just happen if I woke up too quickly in the morning, or if I had an impact on a senstive area like my knee joint. I used to think I just lost consciousness, though since it has been witnessed a couple of times I've been told it's more like a seizure with eyes rolling, shakes and what not.

As I've said, the only times it has happened in my adult life has been when I've smoked cannabis, but only 3 times out of a few hundred sessions, so it's by no means a regular occurence.

the visuals are better than blacking out normally and i get realizations with it .

what kind of realizations ? different than a typical trip? , if there is such a thing

like real life meaningfull reunderstandings - deshadowification - of parts of me that i unconciously create to protect myself from the world
choices iv made and how they currently are effecting me
like short term ego loss followed by a slow re-entry allowing one to disect their daily conciousness's building blocks.

sounds like low blood sugar/pressure. Used to happen to me too until I quit smoking cannabis for about 6 months, and never happens now that I dont smoke daily unless I dont eat enough fruit. There is a direct correlation between low blood sugar and heavy cannabis use and what you have described fits the effects of low blood sugar quite well. The brain requires large ammonts of whole fruit to function properly. We evolved on a high fruit diet living in tropical regions, so not eating enough high sugar fruits throughout the day is like starving the brain I think.

I have also had visuals when it happened to me.

I've gotten mad head rushes before. I don't like the feeling though. I've learned how to dramatically increase the blood flow to my brain by tensing abdominal muscles -- just like high speed pilots. That completely nullifies the effect. I have had some really powerful visions from it. Something about this fusion reactor that was powering my very being. Really weird feeling.

I've suffered from cluster headaches and severe migraines for much of my life. I've had a couple instances with the cluster headaches where the pain was so unbearable that I became really lightheaded and blacked out. It was like you described Phlux-, like I learned something and struggled to bring it back to waking reality. Also, when this happened, I would wake up and the pain would be gone completely or much less in intensity. The first time it happened, when I was about twelve years old, I thought my brain just reset itself because it couldn't take the pain anymore

I still don't know exactly what it is, or what causes it. I've successfully learned to treat my cluster headaches and migraines myself without any pharmaceuticals. The doctors never understood them anyway, and nothing they did or gave me made any difference. They did all kinds of tests on me as well, and couldn't figure it out.