WOOT! Found it! Thx to Disconent Winter for the additional info I was able to find it by doing a fanfiction search on the word "journal" and there it was! (Does happy dance) Now off to read some before work....
Story rated MA so no YIMs!
dokuga.com/fanfiction/story/5702/1
How She Came To Be by Waiting Dog
Kagome Higurashi had it all; a loving family, great friends, and an exciting life few only dreamt of. Lord Sesshoumaru had everything any demon with sense would want; power, wealth, and a strong noble bloodline. How will Kagome fare when everything and everyone she holds dear is taken away? How will a series of journals change everything Sesshoumaru thought he knew about his heritage? Together they must uncover dark secrets, visit foreign lands, and struggle with the very essence of space and time as they face off against an ancient enemy worthy of the kamis themselves.
Rating: MA - Universe: Canon - Status: Incomplete - Category: Chapter Stories - Genre: Action, Drama, Romance - Updated: 02-24-12 - Created: 05-19-11 Chapters: 25 - Reviews: 41 - Words: 86,875 - Reads: 24,409