The last chapter shows the life he had before he became a girl. Also, everyone around him thinks he was a girl from the beginning and he speculates that he's in a parallel world where he was born a girl. The funny part is that he's as unpopular in school as when he was a guy.
@Ildzmer it is about otaku become cute girl, become idol to seperate self from the gloomy future she think she will have.
Gallery is not even close to complete. If you would like to read all, support by buying at http://www.dlsite.com/home-touch/work/=/product_id/RJ211367.html