I resonate completely. I too find lying on my badk particularly triggering.
As for myself, three days ago I left my body 100%. How did I notice?
So long as we intend to return into our body, we will be somewhat kept up-to date as to our body condition, because when we leave our body 100% we only have a certain time window within which we can return into our body, otherwise without our energy in it the entire body organ functions will come to a standstill.
You might wonder why I left my body 100%. I guess I cleansed some stuck energy which wants to leave rather sooner than later, and it needed this experience to feel that I am not done yet here and that I want experience it most wonderfully. So during this Astral experience I felt stronger and stronger how I am not done here yet, and the reason I felt so stronger and stronger was because I felt that I won't be able to return into my body if I wait much longer. Well, and this was the moment when I slowly came back and noticed that my body couldn't breath anymore, hence stopped breathing. There was simply no energy in my body that allowed for breathing. Shortly afterwards I was back in, and well, here I am :)
Bear in mind, the reason I was experiencing these bodily events was only because I was energetically still drawn back into my body and my work and purpose in this reality. Once the energetic work here is done, and nothing holds us in this reality any longer, there is no reason to check our body condition because we don't need this body of ours anymore. Imagine how beautiful our departure is going to be. For my part, I feel the longing to my next life already, unimaginable how perfect the actual process is going to be when we finally get there. Heart explosion I guess :)
Woah sounds like an intense experience, seeing your body unable to breathe anymore! I wish I could leave my body like that and explore the astral plane, but I have a long way to go before I reach something like that.