Don't be too hard on yourself. There are no mistakes. The frustration is normal. In fact it is the very nature of the whole thing.
We might call the "whole" Life - One Life. As the whole, Life does not know that it exists. Imagine yourself as the whole, then try to notice that knowing yourself would be impossible. There would be no measurement, no quantification, no comparison. You would have no basis by which to know yourself.
So the initial expression of Life, the root desire is to know yourself. To know yourself requires becoming a know-er. To be a knower requires the known. That urge to know of your own existence is the birth of imagination. I AM! I AM springs forth naturally, innocently, a simple expression of Joy. We know many times when we have been faced with a situation that could have brought a seeming end to our existence, and after the dust settled, we had the feeling "I AM!" The simple feeling of existence.
That I AM-ness is the initial urge or compulsion to split reality, to split up the whole, your Self or Life or whatever label you like. It is almost impossible NOT to do this, therefore the frustration when we try to see through it, the frustration when it keeps happening. We take this as bad but it is not. It is the natural expression of Life. Believed in, it comes with suffering and then the equal compulsion to go back, to get back to that wholeness - this is the uninvited pull of spirituality.
That urge to split up reality is natural. It is the natural expression of coming to know yourself, coming to know your own existence. There is no way to express without dividing. We see it in our language. To communicate requires that expression of duality. Ironically seeing it for what it is, the game is up. We can no longer be fooled by it. The recognizing of reality as whole, recognizing yourself as the whole, is the recognition that that split was always conceptual, always only seemingly so.
But it is also clear that the incumbent suffering never actually applied. That nothing was ever actually needed or missing. You are the whole, and that whole, that Life comes to know itself through this natural expression. Seeing through it, it continues but there is no belief left in it. It is the belief in it which we are ultimately trying to see through in spirituality. That's all.
Therefore take no grief in this frustration, this confusion. Enjoy this seeming separation, this seeming split while it lasts. The full experience of Joy is only the opposite of the full experience of Suffering. Ultimately even Joy and Suffering fall away when there is no belief in that split.
What remains is only ever what IS - now and now and now and now and only now. The wholeness we call Life or Self or Reality - and that duality is free to express, that split can appear, that urge is the master, then seen through, then known as a perfect expression of the whole.
The world and "I" are not-two.