Why might Nick be upset with Sam? (Please read)?

My friend Nick was texting my other friend, Samantha, about something and somehow he got around to telling her that he cut himself over this past summer. Samantha told her math teacher at school without telling Nick about it, and he was called down to guidance the following morning. Later, Sam told Nick that it was she who told, and now he is refusing to speak to her.

I have a few theories as to why he’s so upset (my mother has depression and was in a similar situation when she was in school, so she attempted to explain her feelings to me), but I’m curious to here if any of the jellies have any opinions as to why Nick is upset or their experiences in similar situations.

I personally believe Sam did the right thing, except perhaps telling Nick ahead of time…although that may have caused him to do something more drastic, right?