'Teen Mom' Amber Portwood Reveals Latest Suicide Attempt, Why She Chose Prison

June 7, 2012— -- "Teen Mom" star Amber Portwood, who this week chose to serve a five-year prison sentence for an illegal prescription drug charge rather than complete a drug-rehab program, is now explaining her decision, her recent suicide attempt and how she believes prison will ultimately help her.

"I took 30 Suboxone [which typically treats opioid addiction] within three days," she said in an exclusive jailhouse interview with ABC News Wednesday, speaking publicly for the first time about trying to kill herself as her life spiraled out of control.

"The depression took over. I'd just take four to five at a time underneath my tongue, and nod out. I had more than addiction problems. I had, you know, mental problems, too."

This was not the first suicide attempt for the 22-year-old Indiana woman, who first starred on MTV's "16 and Pregnant," and whose life later unraveled in front of audience's eyes on "Teen Mom." She was rushed to the hospital last year after boyfriend Gary Shirley called 911.

It was in February that Portwood pleaded guilty to felony possession of a controlled substance and admitted to violating her probation. Her sentence was suspended, however, because she entered a court-mandated drug rehab program.

Her decision this week to leave the program after three months means that her initial sentence has been reinstated. Portwood is in jail, and is expected to be transferred to prison soon, where she could serve two and a half years of the original sentence.

In the interview with ABC News, Portwood said she doubted that she would succeed in the drug-rehab program so she believed it was best to serve her time.

"In my situation, I felt in the program there were a lot of eyes on me. And it was very uncomfortable. I was not using my anti-psych medication even," she said. "You know, I was very depressed, all alone, all bitter at everybody. I felt like that wasn't the life I wanted to live, I felt like I'd rather do my time, and get it over with, and make the best out of the situation that's been handed to me."

Portwood was also slapped with a domestic violence charge after she was shown hitting Shirley, her daughter's father, on an episode of "Teen Mom."

Shirley now has custody of Leah, 3. Portwood told ABC News she started "to feel downhill" when Leah was taken away from her.

"I felt like I had no reason to even be around, because I was a mom. I felt like that's what I was put on this earth to do, when I had her ... and I started partying and doing drugs because I felt like I couldn't do anything anymore. I lost my whole family, I felt like, they moved away from me," she said.

Asked how her absence while in prison would affect Leah, Portwood said she really hadn't been seeing much of her daughter, as a result of the time she spent in drug court and because she and the baby's father didn't have a set schedule for when she could see the girl.

"I lived such a busy life and I woke up sometimes and was like, am I too busy for my family? And I felt so selfish. I was so depressed. It became kind of scary for me," she said. "I felt the same way I felt a couple years back when I, you know, tried to commit suicide. When I walked in a courtroom, I was like, if I don't do something, I'm going to have to."

She said she believes she'll see more of her daughter during her incarceration.