Dropping by Chase on her lunch break in Manhattan, Lauren West-Rosenthal argued her case for a loan.

“I want to quit my job and pay off my credit card debt,” she earnestly told the manager. “Then I will live off the rest.”

She was sent packing — but not before receiving an earful from the bank employee who laughingly told her that wouldn’t work.

“I look back now and think, ‘What on Earth was I thinking?’ ” West-Rosenthal tells The Post about the early 2008 bank visit. “But I was so desperate to maintain a certain standard.”

That standard was living alone in an apartment on the Upper East Side, ordering takeout from fancy restaurants and splurging on glitzy trips.

In the end, her efforts to keep up with the Joneses backfired. She declared herself bankrupt at the age of just 31, after owing $30,000.

Now an older, wiser mom, West-Rosenthal has launched a blog chronicling her exploits, called Not So It Girl. In it, the 41-year-old writer describes her thwarted attempts to become a New York socialite.

“The problem is, I never quite fit in with the scene,” she says, citing her weight issues and lack of family wealth.

West-Rosenthal moved to New York from her native Miami just before her 22nd birthday. She landed an internship at Rolling Stone magazine before being taken on as personal assistant to Atoosa Rubenstein, founding editor of CosmoGirl, in 1999.

After that, her life was a whirl of fashion shoots, parties and celebrity interviews as she climbed the ladder in journalism. She mixed with the likes of Ashton Kutcher, Britney Spears and Anne Hathaway. However, as a size 16 to 18 and, at one point, weighing 220 pounds, the 5-foot-tall young woman felt intimidated. “I didn’t fit the look of the crowd running with these celebrities,” she says.

She remembers spending two days in Hollywood with Hathaway, who was filming “The Princess Diaries 2,” in 2003.

“She picked me up at my hotel in a car and we went to lunch and she ate nothing,” says West-Rosenthal. “She was wearing jeans and a poncho and looked amazing. Meanwhile I was wearing a frumpy black dress.

“Anne couldn’t have been nicer but, as always, I was the mandatory fat friend on the side.”

Feelings of inferiority drove her to spend thousands of dollars on specialist diets, especially low-carb menus, private nutritionists and a fancy gym membership at Equinox. She splashed out cash on Marc Jacobs clothes and Tory Burch shoes, and refused to downgrade from her one-bedroom apartment on the Upper East Side — even though she couldn’t afford the $2,000 monthly rent.

“I wasn’t even making six figures, so it was a little stupid,” says West-Rosenthal, who later wrote three books. “But I wanted [the apartment] because of the image.”

Travel and food also drained her resources. She thought nothing of forking over $70 on a single takeout meal from Mr. Chow’s, and paid out of pocket to fly to ritzy locations such as Park City, Utah, for the Sundance Film Festival.

“I was into networking and living the New York dream,” says West-Rosenthal, who names shoes and bags as her top vices. “I maxed out my credit cards.”

A further extravagance: occasional staycations at luxury hotels such as the Soho Grand, where she would perch in the lobby sipping wine while typing on her laptop. “I’d tell myself I needed to get away from my apartment for the night, even though I lived alone,” she says. “I wanted to write the Great American novel and thought I could only do it in a $500-a-night room.”

By February 2007, she had started at a $90K-per-year job at Sirius Radio producing a range of talk shows, including one hosted by her idol, Candace Bushnell, the real-life Carrie Bradshaw of “Sex and the City” fame. “She influenced me a lot,” says West-Rosenthal, who aspired to Bushnell’s lifestyle of weekends in the Hamptons and taking town cars to appointments.

But Bushnell’s business acumen didn’t rub off on West-Rosenthal, who sank further into debt despite the salary bump. “The more money you have, the more money you spend,” she says.

As time passed, she began to find the work at Sirius draining and demanding. It wasn’t satisfying her creatively and was getting in the way of her writing dreams. That’s when she unsuccessfully approached Chase for a loan, keen to both quit her job and pay off her creditors. But fate intervened and she was fired because of a miscommunication with a boss (not Bushnell) in May 2008.

Panicking about what to do about her finances, she allowed herself to be persuaded to consolidate her debt. This “only made things worse” because the revised interest rate suddenly spiked and proved to be even higher than before.

The situation was so grave that she feared she would have to return to Florida to live with her family. “Nothing feels worse than admitting defeat,” West-Rosenthal says. “After 10 years living in New York, I felt like a true New Yorker and now it looked as if I had to start over again.”

Later in 2008, she consulted a financial lawyer out of desperation. His advice was clear: “You need to declare bankruptcy.” In early 2009, West-Rosenthal did just that.

“For the longest time, I was so ashamed,” she recalls. “When things got serious with my now-husband, Nathanael, I sat him down and said: ‘We have to talk.’ He thought I was going to break up with him, but I wanted him to know about the bankruptcy.”

She finally got her finances back in check after cutting up her credit cards, paying by cash or debit card, relocating to a shared apartment in Fort Greene, Brooklyn, and securing a successful freelance writing career.

“I got my confidence back,” says West-Rosenthal. “I paid my bills on time, monitored my spending and paid myself a ‘salary’ from the money coming in, saving the rest.”

Happily, West-Rosenthal’s revelation didn’t put Nathanael off. They moved in together and, eight years ago, they got married. In 2014, they moved to Stamford, Conn., and now have a 4-year-old daughter, Mila. Nathanael works as a firefighter and paramedic. West-Rosenthal, now a healthy size 6, is still a freelance writer.

“I’ve learned that it was never wearing Tory Burch flats that earned me an assignment or book deal,” she says. “I’m so much happier now that I’m comfortable in my own skin.”

Her advice for aspiring It girls? Get a savings account — “and don’t do what I did and live beyond your means.”