What is this really "letting go"?

 Actually, I don't have a single answer to the question: What is this really "letting go"? But the topic is something I am continuing to explore and want to be able to articulate for myself.
   The problem is, I think, how to approach the question. If the mentality is something like, "I want to make sure that I am always letting go of attachments all the time," then this is already an attachment. It's like saying, "I want to be hyper-vigilant in everything I do and say, so that I can finally let go of everything." In fact, what it leads to is a kind of subtle attempt to control every situation and give rise to certain kinds of thoughts. To truly let go seems quite the opposite: it is to fully acknowledge and even to accept every single mind-state one is in, with the fullest possible acceptance. How is this arrived at? What is the real key to this letting go? I think it's not identifying any thoughts with an enduring sense of self. It is being able to see the thoughts arise and disappear, but never getting fooled into thinking any of that is 'me'. But this is not easy to do, because most of the time a person thinks the 'I' in their thoughts is actually their real self.
    To give an example: when there is a potential layoff in the company or shortage of work, I have a tendency to go to: "what happen to me if I lose my job?" "Where will I find a steady income?" "Where will I live?" and so on. But when I really begin to analyse it, is this "I" that I refer to really the true me? Often, the "I" refers to an image of my body, or a future projected scene where "I" am in a dire situation or even wandering around destitute. But even if this is the body and how it looks to me, is this body "I"? As long as I remain tied to the idea that the "I" in my sentences is really me, my thinking is limited as well. It is as though I were staring at something all day to the point where I am hypnotized into believing that the body is my self.
     A little while back, our Chan group did a Living Chan presentation with Venerable Guo Xing, and one of the experiments we did was to take a rubber arm and place it parallel to one's real arm. The purpose of the experiment is to lead people to believe that the rubber arm is their real arm--to the point where hurling a large weight onto the rubber hand would 'feel' painful. (You can probably go on YouTube and keyword "Phantom Arm Experiment" to see how this experiment works). The point is that as long as a person is lulled into believing that the fake arm is the real one, one behaves as though their life depended on protecting the fake arm.
      The physical body seems to be a bit different from a simulacra like a rubber arm. But the principle is much the same. We are conditioned to take the body be us, so everything that threatens the integrity of that body appears to diminish the mind. But is the mind ever really diminished by anything?
       This practise is not about suppressing, altering or changing the way a person feels. It's not really so plausible to do that anyway, and nor is it necessarily an achievement to be able to change how one feels. The practice is actually the awareness that we are never how we feel, and we are not our thoughts of "I" or "me". To know this deeply is to naturally loosen the hold we have on both emotional states and that effort to present what we consider 'right' or 'wrong' emotions. That is really and deeply to relax. But if I am still stuck on who this 'me' is and how to present it to the world , I am always going to feel tense and anxious, no matter what I do. Something for "me" to ponder!