Eleanor and Park question

The words that were used were easy to be understood by the reader, also there are still some that needs to be looked at the Dictionary. the flow of the story was light and almost execellent, however, I wasn't quite satisfied with the ending. it was an open-ending I get that. but I DIDN'T LIKE MY OWN ENDING/CONCLUSION. I mean, I was heartbroken, how could I end it in a positive way, I know it shouldn't be but I really want to know what happened to Eleanor and whatever their relationship was in the story, I want to know her reasons why she left Park. And what was written in the postcard. I want to know the author's say to this. I was having my heart-breaking-super-emotional moment when I flipped for the next page, I was surprised and shocked to see "ACKNOWLEDGEMENTS" so soon! And I was like "Oh God! This can't be it, right?" "Oh my God! what's wrong with you Eleanor?!" "You can't just leave Park like that! How could you?!" I bursted into tears, tossed and turned and was literally kicking my feet everywhere I face while I lay on my bed and that was around 2am here in the Philippines. It left me into pieces. My heart was shattered. Not disappointed though because it was a really really good book. I want to know Eleanor's POV. I want a SEQUEL. How would the Author end the story her way? but then, of course, I suggest everyone should read this book. The ride's all worth it! <3 :)