People are afraid about the unknown, always, because the known seems so well acquainted that you can remain unconscious with the known; there is no need of any alertness.
The unknown requires you to be more conscious, more alert. And the fear is coming from your false ego, because the more conscious you become, the less is the possibility for the ego to exist. That’s why you are feeling that something is dying in you.
This happens only to the fortunate ones, because anything that can die in you, is not you. Your life source is eternal and knows no death. You can take it as a criterion, that whatever is dying, deserves dying. It was false and you were unnecessarily identified with it. With its death you will realize your reality and that reality never dies – it is always here-now.