My answer requires us to consider a small thought experiment. Image for a moment that you are “God” – which is to say, you are the source and totality of all existence. There is nothing beyond you or outside of you. You have no higher God to pray to. You can seek no higher source of meaning for your own existence. You necessarily have free will because everything you think or do flows from your own nature. But there is one thing you can never know:
Why do you exist?
Perhaps you are the creator of many worlds, and the inhabitants of those worlds can explain their existence by pointing to you, but you are eternal and uncreated, so you cannot point to any higher creator to explain your own existence. You simply exist and there is no possible “reason” for your existence.
What should you do? What is good? What is evil?
Since you are the totality and source of everything, you ARE the standard for everything, including good and evil. You basically just have to do what feels right and have faith in your feelings because there are no higher powers, or principles, or logic, or laws that you can use as a guide for your own behavior.
You are utterly free, and absolutely responsible for everything that happens because everything is an expression of you. You are necessarily an existentialist (ie, you can’t really find meaning in anything beyond your own existence) and you are necessarily a solipsist (ie, everything is a product of your “imagination” or flows from your own nature).
What about all of those creatures you created? They all think they are individuals. Most of them feel isolated in a certain sense – each creature says: “I am the only one who can think my thoughts. I am the only one who can feel my feelings. If I think about it, I can doubt the existence of the world and other people, but I cannot doubt my own existence – I cannot sanely doubt that I am the thinker of my thoughts.”
Each of these creatures feels like an existing being – each one can say: “There is something that it feels like to be me.”
But each of these creatures is a part of you – each is a limited manifestation of your own infinite Being. Thus when they think or feel anything, they are really YOU in the sense that they are part of you, so ultimately their thoughts and feelings are YOUR thoughts and feelings.
Each of them is how YOU experience YOURSELF from their limited perspective. Each of your creatures is a unique perspective that YOU can take upon YOURSELF. Since you are the totality of ALL, nothing in the experience of your creatures is outside of you – not even each creature’s deep sense of being a unique individual being. They think they are all individual entities, but in a certain sense each creature’s most intimate “sense of self” is ultimately YOUR sense of YOURSELF as experienced from a particular perspective.
So you ask me who I am? I am “Existence” taking a perspective upon itself. The “self” that I feel is unique to me is unique in the sense that I am Existence as It views itself from a unique perspective, and I am unique in the sense that, ultimately, there is only one SELF, which is the Self of Existence itself. I am not God insofar as I am the ego of a limited creature, but I “am God” in the sense that all of my thoughts and feelings stem from the same source as ALL – I am what the universe feels like to be me. I am “Being” in the form of a limited being.