Okay wait so for everyone who's confused, she almost called Komi-san 'sister' and realized she was becoming attached to her. Since she had to say goodbye so much in the past, she doesn't want to get hurt, that's what the beginning of the chapter was about. This really continues the theme of communication in this manga nicely... moving on from just a basic fear of speaking and conversing to an internal fear of being vulnerable and becoming attached.
my eyes are sweating, send help