as a female, i can tell you unequivocally that she is playing games with you, and you need to run, fast. you will get over her, promise, and without the deep scarring that would come with trying to "keep" this girl and being constantly disappointed months or years into the future and then thinking all women are like this. doesn't matter how many relationships a person has, they generally are gonna be most influenced by the last relationship they were in. comparing and all that. 6 months is a wound that will heal. trust me. you know this. don't let her make YOU think that YOU blew it. she took your heart and played with it, and SHE is the immature one. sounds like a drama queen, or someone who likes to have alot of guys on the string. WHO in their loving mind would tell you about other guys and imagine your reaction? that is some stone cold BS.
you did nothing wrong. at least, from what you have told us. you were acting normal and in love and she was flitting around sucking up attention, feeling like a femme fatale to boost her ego, sounds like. and any girl who would take 4 months to read a book you lent her is a ninny anyway. get a girl who will read a book in a timely fashion.
not to make light of it, seriously, but you need to realize you were acting normal and she was being a word that would only get censored here if i wrote it. and its only worsened by the fact that you were sex buddies beforehand. she just thought maybe you were relationship material and she completely missed the fact that maybe SHE ISN'T relationship material.
there are, i assure you, other fish in the sea.