Supposedly there are three answers. You are either your thoughts, your body, or a soul. These are more formally known as psychological criterion, body criterion, or single soul hypothesis. The issue arises in one occurrence. The Ship of Theseus is a wooden boat each day gets a plank replaced, but after all its planks are replaced is it still the same ship? Another example arises in teleportation. Your body is disintegrated inside a teleporter after its information is saved and sent and then the information is almost instantly sent to somewhere else to rebuild you exactly as you were. Yet the question is did you die, is a twin created, will it remember your/its past, and will that be you?
I don't get why they arise as such opposite answers. I feel confident to say I am body, its thoughts, and a soul somehow attached. The soul is unique idea because it lives through death. And according to the bodily criterion even if there was a soul that wouldn't be me. And I think of my psychological states as part of my body. But the atoms of my body don't know about me or the thoughts I have. Yet if I rebuilt my exact brain and memory into a new body "I" would have two bodies according to psychological criterion. They aren't so different. And I can only say I am all three if I hope and believe my soul is something physical. I hope and believe my soul is physical but not made of matter but of energy. Since matter can take the form of life then I don't see why energy can't, since matter is technically a form of energy as said by Einstein. And I hope and believe this unique undiscovered energy exists with the body and remains after it dies and goes on to fulfill other roles in the universe, possibly eventually to work its way to other become new bodies for new things. Perhaps human bodies are merely USB ports for these souls.
Who Am I? I am my body, thoughts, and soul all at once!