She's also saying sorry for all the trouble resulting from an audit of her expenses and the resulting media frenzy.
A letter to the editor from Wallin, who left the Conservative caucus and now sits as an independent amid ongoing publicity about her expense claims, appeared in Wednesday's Wadena News.
Wallin said she was apologizing to family and friends "who have been hounded by the news media" as well as to taxpayers who deserve to know how public money is being spent.
"I'm very embarrassed that the people of my home town, who so generously named a street after me, have had to go through all of this," she said.
"It's taken a toll on my family as well, and it has changed my life forever — the leaks and lies and insinuations that I am some fat cat or a cheater, and the disturbing calls and emails, some of them uglier than you can imagine."
Wallin suggested part of her problem stems from the way the Senate accounts for trips to Saskatchewan.
She said because there are so few direct flights from Ottawa to Saskatoon in the evening, she faces a 1 a.m. arrival time — too late to drive to Wadena.
Rather than bill taxpayers for a Saskatoon hotel room, she said, it was better to stay overnight at her Toronto apartment and then fly to Saskatchewan the next day.
However, by doing it that way, the flight was classified as "other" rather than a trip home, she said.
Wallin also appeared to address lingering questions about her eligibility to represent Saskatchewan in the senate, noting that she spent 168 days in the province last year.
"Even though the only thing you are required by law to own is $4,000 worth of property, I have a cabin at Fishing Lake and co-own houses in town, and I've paid my property taxes and bills here for years," she said
An independent audit firm has been reviewing Wallin's travel expenses going back to January 2009, when she was first appointed to the Senate by Prime Minister Stephen Harper.
It has been reported that Wallin has claimed about $350,000 in travel expenses since September 2010.
In an interview with the CBC's Peter Mansbridge earlier this month, she said she has paid back $38,000 in expense money.
More could be paid back when the audit is released later this summer.