Betrayal of a close friend

I am a writer and my best friend Aggie (name changed) is also a writer. In 2015 we have published our books under the same publishing company. Then I have sent her my first message. I did my best to be a great friend, I supported her as much as I could. I read her stories, wrote fanfictions for her, drew fanarts for her. Two years later she read my new book and sent me a hate review, saying that my characters were "brainless" and telling them to kill themselves. I confronted her about this and she said that she exaggerated and apologized. Things went smoothly for 2 months, when I looked through the old reviews of my novel. I got new hate comments and very low ratings. I tracked the profiles of haters and discovered that the haters were fans of Aggie's books and gave her long postive reviews and very high ratings. The haters' accounts were all connected one to another, and to Aggie's account, and one's name was Aggie's old name. I confronted her about it, and she said that I was paranoid and that I keep accusing her all the time, and that my book was probably lousy if I got such bad reviews. I am shattered. I don't know what's worse, that I lost a friend I trusted or that my book got unnecessary bad reviews because of all it. ;_; Can anyone encourage me? I feel really depressed.