If I'm not this body then who or what am I?
We're all spirit souls, parts of the Supreme Spirit Whole (Krishna), and meant to cooperate with Him. Each of us is a unique person with unique likes and dislikes, talents, abilities, quirks, and a unique relationship with Krishna. We're eternally individuals. We're not all the same. Our spiritual identity isn't "one size fits all," but realizing who we really are takes time and practice; we need to practice acting like spiritual beings.
Right now, we're inside—and very attached to—perishable material bodies. We're so attached that we think we are these bodies. Our desires and actions center on what we think will make "us" (our material body) happy. We think "looking out for number one" is the number one most important activity. That's false ego.
Real ego means to love the ultimate reality: the supreme whole, the greatest person, the Supreme Being. We're naturally happiest when we can make someone we love happy. If we act selfishly, it doesn't feel right. We can pretend we're the center of the universe for a while, but eventually reality comes knocking.
In our conditioned state (subjected to conditions like birth and death) the natural activities of our real self—loving service to a Person infinitely greater than we are—seem unpleasant to us, in the same way that sweets taste bitter to a jaundice patient. But sugar cures jaundice, and practicing Krishna consciousness cures our aversion to Krishna. Gradually, as we practice Krishna consciousness, Krishna reveals His identity and our own identity to us.