Perishing of the Ego

What is the ego? A person's self-importance or the part of the mind bridging the conscious and unconscious to create one's identity? How about a defense mechanism instilled into every living being for survival? I feel like surrendering to my higher self because I clash a lot with it. My thoughts want one thing whereas my spirit craves more than what's being put into my stomach. This battle is taxing on the physical body and if I don't stop it soon, problems will arise. I'm saying that to say I'm ready to walk in the light. Come.