345A: Geometric Mood Diary (Solved!)

I have been searching for a book for a few years now without much success. I read it between the ages of 7-10 (I am 43), it was a chapter book in a diary format, the cover was black and white (maybe speckled?) and each diary entry had some sort of drawing — I want to say a geometric pattern to describe the mood of the entry. That is all i remember, besides the fact that I loved the book and continually checked it out from the 79th street public library in NYC.