You asked: What is the scariest part? I answer; "The scariest part is not is the not the feeling of loneliness, or the darkness that fills you despite the looming pain of emptiness."
The scariest part is the realization is that you may have lost yourself completely. sinking in as you lay at 3:00. a.m. because you've lost the ability to sleep. and you can't even cry, because you don't even care..