Dear diary, my dream holiday just turned into a nightmare!

An Australian woman claims she was thrown in US immigration detention after arriving in Hawaii for a romantic getaway with her boyfriend — because officials read her diary and decided she had no plans to go home.

Molly Hill, 26, was so determined to have a long vacation with her American lover that she resigned from her marketing job before beforehand — but she had a tourist visa for 88 days and had booked and paid for return flights back Down Under.

“They were convinced I wanted to immigrate illegally because my diary had notes like ‘going away drinks’ and ‘last day at work’, things I got in order before expecting to be away for three months,” she wrote in a Facebook post.

She says officials were suspicious of her from the moment she arrived in Honolulu because of her American boyfriend, and swiftly hauled her off took her to an interrogation room while they rifled through her luggage — and her diary.

After six hours, they slapped her in cuffs and took her to a detention center, where she was stripped and searched in an experience she described as like “Orange is the New Black” “but with locked cells.”

“I couldn’t believe I was in the same place as the chick whose boyfriend convinced her to drive 70 lb’s of heroin and meth over the Mexican border,” Hill wrote.

The officers in detention were at least friendlier than the immigration officials, she says. One told her, “You shoulda fell in love with a Canadian!”

The next morning, she was marched back into the airport in handcuffs, charged $620 for a flight to Sydney, and put on a plane home.

US Customs and Border Protection told News.com.au that officials believed Hill planned to get married in the States and had the wrong kind of visa.

“Hill applied for admission as a visitor for pleasure (which means that she is only eligible to stay in the United States for a brief period of time) under the Visa Waiver Program (VWP). However, upon inspection, CBP officers found that Hill presented conflicting information and was determined to be inadmissible under the VWP,” the agency told the site.

A source told Buzzfeed that officials suspected Hill and her beau were headed to the altar because she was carrying “birth certificate, old passports, college transcripts and training certificates in her luggage” — but the Aussie claims she just keeps all her personal documents close at hand, and they had no plans to tie the knot soon.

Hill’s former employer told the Herald Sun that it wasn’t at all unusual for her young staffers to resign ahead of lengthy trips away and that she planned to hire Hill back again when she returned.

“I do that for all my staff who want to take holidays for an extended time. If you take more than six or seven weeks you need to resign. I don’t think that’s unreasonable for companies,” Mini Sarkissian told the paper.