Yes I've read it - it was heart breaking! I was the same; studied Russia in 20th century but never touched upon the gulags. Frightening to think that such places still exist today. I think I might re-read it now actually.
Has anyone read Between Shades of Gray by Ruta Sepetys? I read it last year and still think about it. I was pretty angry actually that I'd studied the Communist Russia and the Cold War at A-Level but hadn't heard much about the gulags, other than that they existed.