This video by CGP Grey claims that you're not one but "You are two". Watch the video to know what it means -
But here's my hypothesis -
If you open a complex machine you'll find it is made of hundreds of smaller machines and those smaller machines are probably also made of even smaller machines connected together.
Consciousness is a similar thing. My hypothesis is that there isn't one consciousness or two as the video claims but there are many more. All different consciousness working together to create an impression of one single consciousness. The "I'ness" as we call it.