LISA MARIE PRESLEY’s friends fear she’s headed for a career-ending meltdown as she struggles through a disastrous comeback tour.

The ENQUIRER was on hand for the start of the singer’s first con­cert series in five years, and it was apparent that El­vis’ daughter is plagued by several scary problems.

Despite her high expectations, Lisa Marie attracted a pathetically small opening – nig ht crowd.

At New York’s small Gramercy Theater on June 14, the tired-looking performer played just six songs to a half-filled house.

“It had to be dis­appointing for her to come out and be greeted by 400 people at most,” said an eyewitness, “but the most surprising thing was she looked rail thin”

The King of Rock and Roll’s 44-year-old daughter appeared unsteady on her feet as she performed songs from her latest album, “Storm & Grace.”

“She was dressed in a red blazer and long black maxidress,” said the eyewitness. “She had on heavy black eyeliner and looked gaunt and tired.”

It was just the first stop on her 10-date tour, and fans were stunned and disap­pointed when she played for only 45 minutes – and used a throat spray after every song.

“She tried to make light of it, tell­ing the audience, ‘I have a new health problem. I’ve got to spray my throat …I know it’s stupid. I’m sorry!’” said the eyewitness. “She did everything that she could to keep her throat moist, including drinking Gatorade she kept onstage. But her voice still sounded weak.”

After the show, Lisa Marie revealed to some fans and an ENQUIRER reporter why her weight had plummeted: “I’ve lost a lot of weight because I’m stressed out. That’s my weight-loss secret – too much damn stress.”

A friend of the singer told The ENQUIRER: “There’s fear among her pals that Lisa Marie won’t make it through this concert tour. Fortunately, she has her guitar-playing hus­band Michael Lockwood in the band, and he’s always there to support her.”

Dismal sales of Lisa Marie’s latest album are adding to her confidence-crushing stress.

“Despite her enlisting the services of famed producer and Oscar winner T-Bone Burnett, her album limped in at a lowly number 45 on the Billboard 200 album chart after its release in May,” said the friend.

Now, a month later, it has dropped off the charts altogether and has sold a paltry 15,000 copies.

Lisa Marie’s comeback struggle would break her father’s heart, and an insider told The ENQUIRER: “Her tour is going to be grueling and no one wants her to have a meltdown.”

Over the years, luckless Lisa Marie has suffered a variety of medical and weight problems. To add to her stress, she is at odds with her mom Priscilla over her decision to cut her ties with the controversial Church of Scientology, as The ENQUIRER recently reported.

“Lisa Marie has been riding a roller-coaster of emotions for months,” said the insider. “Her dream was always to be a big star like her father.”