While I'm glad to hear you're winning in the stuggle with an eating disorder, the market for such a book is going to be limited. Essentially, what you've been through, while awful and requiring huge determination and strength of spirit to overcome, is not unusual. Thousands of girls and women faced the same struggle, and many wrote books.
So you're going to have to bring to the table something none of their books has offered, something which makes the subject marketable all over again.
This is not impossible--it's just real hard. The same situation exists with books about child abuse, yet I know an author whose memoir is doing quite well, because of the juxtaposition of her story played out against a court case against the abusers many years later. She brought something different to the publisher, something which sold.
This is not to say you shouldn't write your story, but you cannot expect to sell it. The writing alone may prove cathartic, though, and if you can sell it, and sell 5,000 copies (modestly successful), you could earn anywhere from $3200 to $12,000 depending on what size and type of book it is and its retail price.
I'm still really pleased to hear you beat this, though.