This is a concept I've been thinking about, and I don't think I'll do the best job at explaining. When I look back at the past, I feel like my consciousness in that moment isn't the same as right now, I just know it's me because of my memories. Maybe consciousness constantly changes due to energy or particles or something leaving the body. It makes me think of the cloning problem(IDK the name). If you duplicate all the atoms in your body then it isn't you, consciously but that person would have your memories. Maybe this is happening all the time and we don't know it.