Who Am I? You are The One experiencing itself as an aspect of All That Is.
All That Is is consciousness expressed as energy vibrating at different frequencies. Different frequencies create different realities, dimensions and universes as you know them, and everything you can imagine, and beyond. You are consciousness expressing itself as energetic frequencies which create your reality. You can choose to experience yourself as in those realities, or as the reality itself.
There is only one moment, but you can break that moment up and experience it as a series of moments, and call it time. There is only one place, but you can break it up and experience it as endless space, and call it the physical universe in which you live. You decide. You are the one making it all up and choosing the point of view you take.
You have chosen to experience yourself as separate in a limited physical reality, but you are actually not separate from anything, you are just limiting yourself by focusing through the idea of a physical body. It is just the perspective you are presently choosing. You are All That Is choosing to experience itself as a separate aspect of itself. This is just one expression of yourself. You and all the other aspects of All That Is are in the never-ending process of expressing yourselves in every possible way you can imagine.
You experience what you choose to believe you experience. Whatever you project out, you get back because it is all you that is coming and going. You are constantly changing, because in order to exist you must constantly be-coming aware of yourself. You are amazing beyond your wildest dreams.