Kathleen Folbigg complained of getting a "raw deal" in letters from prison tendered at an inquiry into her conviction.
The 55-year-old was convicted in 2003 of murdering her three children and the manslaughter of a fourth.
A bundle of letters has been tendered to the inquiry before former NSW chief justice Tom Bathurst KC, spanning several years and running to more than 130 pages.
In the letters, Folbigg tells a friend she struggled to sleep in prison, stuffing tissues in her ears to block the noise.
"So bad at times that I have unsavoury thoughts about the noise makers - so not like me - ha!" Folbigg wrote.
"So keep that in mind if you reach your witts (sic) end - ha!"
She writes she will be spending significant time in prison, although there was a "shot of medical or genetic miricle (sic)".
Folbigg said she might have been able to get out of prison earlier for good behaviour, if she'd been handed a life sentence.
"Either way I got a huge raw deal," she wrote.
Diary entries that played a role in Folbigg's convictions will also be examined in the inquiry, including evidence from forensic psychologists and psychiatrists.
"How they got away with using them against me is still amazing to me," Folbigg wrote in 2003.
In other letters she wrote there was "no hurry" to visit, and laments her non-parole period was only cut by five years, after an appeal lowered her maximum sentence to 30 from 40 years.
"I don't reckon they really considered anything ... such a "just" legal system that we have in this country," she said.
"While ever my name is attached to words like 'serial killer' I have no hope of ever being heard fairly or otherwise," Folbigg wrote in February 2005.
Folbigg agreed the diary entries "'sound' atrocious" in another letter some months later.
"All I can say is that at the times in question I wasn't in a good positive frame of mind," she said.
A 2019 inquiry concluded Folbigg's guilt was "even more certain".
NSW Governor Margaret Beazley ordered another inquiry following a petition from scientists after the discovery of a genetic variant known as CALM2 G114R in Folbigg and her two daughters.
Immunologist Carola Garcia de Vinuesa told the inquiry on Tuesday significant new evidence has come to light since the previous inquiry, improving the likelihood the variant affecting the production and binding of calmodulin protein could cause disease or death.
"I think my confidence is increasing ... because of everything we are learning about this particular variant thanks to all this functional work," Professor Vinuesa said.
"Every single assay has pointed to pathogenicity, there hasn't been a single assay that has pointed to it being benign."
Under questioning from counsel assisting the inquiry Sophie Callan SC, Prof Vinuesa maintained she was advocating for science, not for Folbigg.
Interviews she gave a US-based science magazine for a December 2021 article expressed her personal view about Folbigg's innocence, Ms Callan suggested.
Prof Vinuesa said she thought some conversations she had with the author were "off the record".
She confirmed she wrote an email to Folbigg's lawyers, quoted in the article, saying she found it "hard to believe there is someone sitting in jail for this".
Prof Vinuesa had not yet conducted genomic analysis, only read Folbigg family medical records.
However, she had not formed a view on whether Folbigg was guilty.
"I had read about the children, particularly two of them being very sick and one of them having myocarditis ... so I thought it definitely warranted a genetic investigation," she said.
Prof Vinuesa will continue her evidence when the inquiry resumes on Wednesday.
