Well it's not a bad start, but there wasn't much of an introduction to the main character. Also, you made this a second person fic and it's a lot harder to read and write. There aren't many descriptions either, it's harder to visualize the story.

The structure of the story seems cluttered and nothing is isolated, it's easy to loose your place. Things like the diary entry should be isolated so it won't be confused with the rest of the text.

I also feel like you over-used Deidara's "un." it doesn't need to be at the end of every sentence.

I'm sure if you try to improve on these things it will be much easier to read.