Queens medics mistakenly declared a distraught woman dead after she shot herself in the head Thursday morning — then stunned cops discover she was still alive and transported her to a hospital where she eventually succumbed to her injuries, sources told The Post.

The unidentified 32-year-old woman was on the phone with her boyfriend in Ohio about 9 a.m., telling him she was deeply depressed and threatening to kill herself, police sources said.

Suddenly, the boyfriend heard a gunshot over the phone, and quickly hung up and called the victim’s sister, who lives in New York.

The sister immediately called 911, and EMTs from Jamaica Hospital arrived at the injured woman’s home at 103-26 115 St. in south Jamaica to find the woman crumpled on her bedroom floor with a gunshot wound to the head.

They tried to revive the woman, who sources said was bi-polar, but determined she had no pulse — and pronounced her dead at 9:24 a.m.

Detectives then arrived at the home and began an investigation to rule out foul play and determine what happened.

As they were searching for clues, they suddenly realized about 10:40 a.m. that the woman was still alive and “making noises,” sources said.

Cops called the EMTs back to the scene, and they rushed the woman to Jamaica Hospital.

Later on Thursday night the woman was declared dead, a second time, sources said.

The woman’s sister, who would not give her name, was furious at the mix-up — and said her sister would have had a better chance of recovery had she been rushed to the hospital immediately.

“I asked the [detective] why it took them an hour and a half to get to her to the hospital. They didn’t have an answer. He told me ‘I’m sorry I don’t really know.‘ He kind of brushed off the question,” she told The Post.

“If she had gotten the help sooner maybe she wouldn’t be in this condition and they would have been able to help her.”

She said detectives even offered condolences to a friend of the woman’s who was in the house at the time before they realized she was still alive.

“They told her sorry for your loss,” she said.

She said she was left to believe that her sister was dead for nearly 90 minutes.

“The investigator called me to say they were sending a detective to pick me up. They first told me to go to the 106 precinct. About an hour and a half later they said go to Jamaica Hospital. I had no clue that this happened. I’m just stunned to hear this.”

A spokesman for Jamaica Hospital would only say that the incident was under investigation.