WWW- Miss USA Tara Conner is “a completely different person” since going through rehab, she tells PEOPLE in an exclusive interview.

“My life has completely changed,” she said Friday. “I’m a completely different person out of rehab. Before I entered rehab I hardly knew who I was. I felt like I was floating and I just needed someone to pull me down.”

The Kentucky native, who turned 21 on Dec. 18, initially entered a rehabilitation center in Pennsylvania on Dec. 21, following allegations of hard partying, indiscretions with men and unreliability. She spent 31 days there – including Christmas and New Year’s Eve.

“I didn’t think I had any kind of issue going into rehab. I even said, ‘I’ll get some free therapy,’ or something like that – and that was so ridiculous,” says Conner. “But I’ve realized I do have an issue. I suffer from the disease of alcoholism and addiction. And if there’s anything that I want people to know it’s the severity of this disease and what it can do to people.”

Conner almost lost her crown after reports of her wild behavior surfaced in December. However Donald Trump, co-owner of the Miss Universe organization, offered her a second chance.

In her interview with PEOPLE, Conner also admits that she tried drugs in addition to alcohol, and that she took her first drink at the age of 14. She checked out of the Pennsylvania facility on Sunday.