She's 14, depressed, and on the internet. help

...she is particularly addicted to Tumblr, which is still worrisome.  Tumblr is like a landfill for everyones secret thoughts, insecurities, and quiet quirks.  I don't want my kid exposed to that.  I felt pulled to look over her shoulder at the Tumblr screen, and she asked me to "please go away," right after she quickly closed a Tumblr window.  Only God knows what her post said.  God help me.