Jane, I had no problem accessing my own notes under notes/reviews under my bookshelf, that was how I finally edited my May 8th note on May 9th. It was always in the database, I can access it either there or via notes of that book in the library. It was just not displayed via the all latest notes link for a period of time.
The May 9th note, I also entered at end of the day, because of the problem I had with the previous note, I checked to see that it was displayed on the latest note list before I went to bed and the next day when I checked, it was gone again.
Now this morning, I entered yet another note on the same book, so far it is still being displayed on the first page. Waiting to see what happens when it drops down to the second page.