Here's what she says in an interview about messages in her songs:

"normally I go from melody and chords to arrangement and start from a musical side, then lastly write lyrics and search for some kind of message. I hate messages! When making a song, there should be a story or some main emotion in it. When writing, I wonder ?What kind of stuff did I just write?? When I?m thinking ?It?s kinda sad, but kinda happy?? all the sudden I think of a word and work that word in. When writing, I always have a goal, or I?ll want to go in a particular direction."

and

"Whether I?m writing ?Traveling? or ?Be My Last,? inside of me there is always a goal. That?s why in interviews when I?m always asked ?What is the message in this song?? I?m always like ?Well, there really isn?t one?? If I think that the message in inside of me, then it?s always the same in each song. It?s the loud anger-like feeling deep inside my chest. It really is anger. Normally I don?t get angry, or argue or get ticked off. If everybody had some quota of anger, all of mine would be stored in my songs.?

(credits for the translation: Translated by: Grayzkule, Provided by: GhostDog, Revised and Edited by: Sanosuke)

every song she ever wrote and sang, is usually telling a story about her life, wat she has been through, and didn't she said she would like to be a manga artist

it kinda is the samething isn't it

instead of drawing a story, she is telling it with music and melody and thats awesome i think