Sekai no Chuushin de, Ai wo Sakebu (2004)

"I thought I might be using a lifetime's happiness in a moment. I was that happy, and she was that beautiful." A young boy stands on the red earth of Australia under its blue sky. It is 17-year-old Sakutaro Matsumoto. His time with the girl comes back to him. The colored sand runs through his hands, and a tear appears on his cheek. He wakes up. It's 2004, and he is 34 years old and in Japan. He thinks, "I have been in a world without her for 17 years." Returning home to see his old high school for the last time before it is demolished, Saku confronts anew the loss of the love of his life, Aki, to leukemia 17 years ago. Now a medical researcher at graduate school, he has lived as if half of him died with her since then. Based on the bestselling novel that sold over 3 million copies, the past and present come together in this love story that is both pure and sad.

If you cried 1 liter of tears while watching "1 Liter of Tears" then you will cry another liter while watching "Crying out Love, in the Center of the World."

This was adapt in a japanese novel in make into a movie.

Takabayashi Matsuri learns that she only has 10 years to live due to an incurable disease. She decides to not dwell on her life and not to fall in love, but she meets Manabe Kazuto at a school reunion.

~~ Adapted from the novel "Yomei 10 Nen" by Kosaka Ruka

Stars the same main actors Ayase Haruka and Yamada Takayuki
they play a young couple in love in both dramas.

It's based on it, so the plot is similar. I guess you will like them both and if you do you should also try the J-movie (Crying Out Love, In the Center of the World) and maybe the K-movie (My girl and I)