The three sentences that identify this excerpt as a memoir is
1.) Hitherto, I had suffered alone; now my little one was to be treated as a slave
2.) I thought of the time when I was formerly sent there out of revenge. I wondered for what purpose I was now sent
3.) At noon I was allowed to go to Ellen. She had sobbed herself to sleep, I resolved to obey orders so far as duty required; but within myself, I was determined to make my stay as short as possible.
These three sentences give insight to the authors thoughts and her emotions.