Abingdon .:
I'll add that tonight, before the multiple eyegasms, I was feeling something that's I'd describe as anxiety, or nervousness, or fear. Maybe that was Dukkha Nanas. But that comes after the A&P, not before (although it was after yesterday's, so maybe that counts). If you told me I was cycling, I'd probably believe you. If you told me that I was bouncing around randomly, I'd probably believe that as well (although my current understanding is that that doesn't happen). If you told me I was completely wrong and had no idea what I was talking about, I wouldn't argue that either. ;-)
I'll also add that I've never seen or experienced anything that I'd confidently label "vibrations." I can detect tingling in my sense of touch wherever I chose to focus; I can see "pixilation" or "TV snow" or whatever you choose to call it in my vision, and I can hear a "white noise" type background in my hearing. But none of it strikes me as particularly "vibratory" -- which to me would seem to need some sort of periodic or cyclical component. This feels more random and chaotic, and I've always just marked it down as being the noise floor of the nervous system. (I'm an engineer by trade -- can you tell?)
Was your pre-eyegasm unpleasantness accompanied by "body stuff" like weird postures or feelings like your body is in an uncomfortable position, or perhaps tension headaches/neckaches/backaches that are unusual for you during meditation?
What you describe as "not what you would confidently label vibrations," I personally would definitely consider what the term "vibrations" is trying to talk about. They manifest differently to different people and in different sense doors. At any rate, if you're paying close enough attention to your sensations to notice these phenomena, whether or not they're "just" the noise floor of the nervous system, you're doing vipassana right. That is, so long as you stay out of content. I'm going to advise you right now that you may currently or in the near future find it a bit more difficult to stay out of content, but now is the time that you will benefit the most from staying out of content. So please try and stay mindful of how valuable that meditation instruction is, and how much it helps you to follow it closely.
Has the nature of the vibrations changed after the eyegasm experience? Even in very subtle ways? Also, does your attention or concentration feel or work differently in any way? If so, could you please describe how? If not, then don't worry -- trust me, what ever you did was working fine.
On being an engineer -- great! I bet having the type of personality that is well-suited to engineering will be helpful to you in wading through all this technical stuff. One caveat is that it's so easy to get lost in mapping and technical nitpicks that sometimes one can forget to just sit down and watch sensations happening. So, if you're having any sort of meditation-related problem, try and always consider "staying farther away from content and doing more vipassana" as one potential solution. If you keep that in mind, then your technical mind will be a great asset to you as you can arouse the curiosity and energy to perform this type of hardcore meditation.