SOLVED. YA book: diary about the coming-of-age of a singer [s]

[Teno]

So I read this book waaaaaaay back, when I was eleven of something. It was a standard length YA novel written in diary format, about a girl who was part of a rock or pop band at her high school. A lot of things had been going wrong with her lately, and on the back cover above the dsecription it said something like "I can't do anything right." I think the cover was black and white mottled, like a cowskin.
The book ended after the girl went to a battle-of-the-bands, or something, and she performed successfully.
There's a scene in this book where she arrives home late after a rehearsal, and she's all sweaty, and her little brother asks her if she's been making out. (She wasn't, but I think she started dating someone later on in the book.)
Also, her best friend was named Sunny or something. (I don't know why I can remember this but not the name of the book.)
There's also a short entry in the diary, that went something like:
"sUUNNNYAAAA TURNEAAD ATHE CAAAAPS LOCK OOOOON
SHES PRESING AAAAAAAAAAA
There! I fixed it!"

So, I can't for the life of me remember the name of this book. Can anyone help?

[Danielle]

I haven't read it but maybe My Name is Chloe.

[Teno]

No, that's not it. I don't remember anything about God mentioned in the book. But thanks anyway.

[Cathy]

How long ago were you eleven?

[Teno]

About five years ago. But I don't see what that has to do with finding this book...

[Dylan]

If you read the book when you were eleven, and you were eleven five years ago, then the book must be at least five years old.

I'm fairly certain the book is Maggie: Diary 1. It's a diary, the girl's a singer, she has a best friend named Sunny, there's a battle of the bands and the back cover fits your description.

[Cathy]

Dylan, that has to be it. I searched inside the book at amazon and the entry that Levina described with fixing the caps lock is there.

[Teno]

Dylan wrote: "If you read the book when you were eleven, and you were eleven five years ago, then the book must be at least five years old.

I'm fairly certain the book is Maggie: Diary 1. It's a d..."

Yes, that's definitely it!
Thanks guys. I've been wondering what the name of that book was ever since I joined Goodreads and now I know. Solved!