I have the same kind of thing and every doctor I’ve seen so far has no idea. Out of the blue I’ll suddenly feel like someone is tightening a belt around my head, I start shaking and sweating and then I’ll just wake up 5 – 10 minutes later (it’s happened for 30 minutes once). But during that time apparently I’m still conscious and talking according to people that have been around me at the time. Apparently I don’t have much memory I’m pretty out of it and am not myself. Then I just click back to reality with no idea what just happened it’s extremely scary. This is also the only thing I have found on the entire internet that is relatable in any way..