Nearly six weeks after "Jersey Shore" cast member Mike "The Situation" Sorrentino left rehab, he's now speaking candidly about his struggle with drug abuse.

The 29-year-old reality star opened up to MTV News about how he became addicted to prescription pain killers and his experience in rehab.

"My addiction was prescription painkillers. At first, I'm sure I thought that it might give me energy. I thought it helped me, because it's a painkiller so you're not tired anymore," he explained. "Then after a while you're like 'Oh maybe this is going to help my schedule out.' I for sure made a mistake by picking a substance over what I previously chose, which was fitness."

Given that prescription painkillers aren't generally known for their energetic properties -- but rather for inducing a feeling of euphoria, relaxation and sedation -- Sorrentino's vehement denial that he had a problem with alcohol and other substances like cocaine seems somewhat suspect.

"It was strictly painkillers and I never mixed them either, even on 'Jersey Shore,' which obviously people have seen me with a drink in my hand and I was never drunk. I was the guy that was the ladies man. You know, you can't get girls if you can't speak to them. So drinking was definitely not an issue for me," he said.

The reality star, who spent only three weeks in treatment at Cirque Lodge in Utah, also recounted his first few days inside the rehab center.

"Your first day [in rehab] is detox. It's not a pleasurable experience at all. ... In the beginning, for sure, when I was [at the facility] in Utah, I'd wake up and just be extremely disappointed with myself. Like, 'I can't believe I got here. How did I get here?'" he said.

For more on Mike "The Situation" Sorrentino's experience in rehab, click over to MTV News.

More stars who've struggled with addiction:

Loading Slideshow...
  • Robert Downey Jr.

    After years of struggling with cocaine and heroin addiction and serving jail time, the actor is clean and sober.

  • Amy Winehouse

    Singer Amy Winehouse was found dead in her London home on July 23, 2011. The 27-year-old singer's life was cut short due to accidental alcohol poisoning. <em>CORRECTION: In an earlier version of this slideshow, the date Ms. Winehouse died was incorrect. She died on July 23, 2011.</em>

  • Lindsay Lohan

    The 25-year-old actress has spent the last five years in and out of rehab and still stuggles to stay sober today.

  • Charlie Sheen

    In February 2011 Charlie Sheen claimed he was clean of drugs and alcohol, but high on himself. The actor has publicity struggled with addiction for years, but many doubt his claims of sobriety.

  • Drew Barrymore

    Drew was famously an addict as a child. By her own admission she said she had her first drink at 9, began smoking marijuana at 10 and began using cocaine at 12. By age 13 she entered rehab and has maintained her sobriety since.

  • Robin Williams

    The comedian overcame a cocaine addiction, but headed back to rehab after 20 years of sobriety in 2006 to address his issues with alcohol.

  • Fergie

    The Black Eyed Peas singer kicked a crystal meth and ecstasy habit.

  • Heath Ledger

    An accidental overdose of prescription medication killed the actor on Jan. 22, 2008.