When it happend it also reminded me of the A&P, but also of SSRI withrawal symptoms (brain zaps; which can't (?) be, because i haven't taken them for years). The strange thing was that this locking in feeling which seemed to paralyze the body everytime for a fraction of a second happened so often in succession, that i thought it would just go on and on without me having any control over it (which made me think of little seizures... O_O)
Yeah, I get what you mean about the SSRI zaps and I can see why you'd be reminded of them. I'm fairly confident that what you're describing is the same thing I'm thinking it is and it's definitely a 2nd jhana thing; whether or not this is actually anything to do with seizures, I have no idea, but if you're concerned then consult a doctor. I know it's probably nothing to worry about, but I figured it's worth mentioning anyway to be on the safe side.
Directly before the first event i was mindful of every little vibration in the third eye.
Almost certainly A&P-related.
The third experience happens often on its own: e.g. when i am noting while walking around, when i am lying down to sleep (even without being mindful). It started a year ago. The frequency was high in the begining then it went away and now it is happening again one to several times a day.
Again, you're probably hitting 2nd jhana with some regularity; would I be right in thinking that, during the time the frequency of these sorts of things began to reduce, your practice had slowed up somewhat?
If I could suggest anything, it would be, while you're sitting at least, paying more attention to the sensations themselves and how they arise without any effort, how they vanish as just quickly and effortlessly, and how clinging to
any of it causes this weird, annoying mental tension. The level of detail you're noting, while impressive, is not required for progress and may just be what's preventing you from moving forward; try taking a wide-angle sort of perspective while observing those sensations, rather than going in for the kill just ease up on the tight focus and let your attention do what it wants to do. The focus and the width of attention changes with each ñana, use it to your advantage rather than trying to control it and you'll save yourself a lot of work.