How Having HIV Has Changed Charlie Sheen

— -- Charlie Sheen is hoping some good can come out of his HIV diagnosis.

"I guess certain things happen for a reason," Sheen, 50, told People in a recent interview. "And maybe all of the stuff that I've done professionally, to garner such attention and fanfare and whatever else -- good or bad -- was sort of leading to a greater calling, a deeper calling, rather than fiction."

Sheen was first diagnosed in 2011 after landing in the emergency room for what he thought was a brain tumor. But he only went public in November after years of what he called "blackmail" to keep his condition hidden.

Since then, he feels liberated.

"I didn't know how relieved I was going to feel afterwards, until I transitioned through that," he said. "But it's been night and day: taking the bullets out of their guns and also freeing myself. There's such pressure, this sense of: The other shoe's going to fall any minute now. You can't live like that. The stress is incredible. Every time the phone would ring, like, 'Oh, jeez, it's another something.' So to have all that gone? What a relief."

Besides being open about his HIV-status, Sheen is more accepting of it, too.

"You can only walk around like, 'woe is me' for so long before you either stay there, or you wake up and do something about it," he said.

As such, he has partnered with condom company LELO HEX as a brand ambassador.

"You spend five seconds putting [a condom] on, and you prevent a lifetime of stress, potentially," he said.

Sheen is also more than half way through a 14-week Food and Drug Administration-approved test trial of a new drug called PRO 140 from the company CytoDyn.

"I'm really excited about being on the cutting edge and being a part of something I think is going to help a lot of people," he said, adding that the new drug is helping him stave off advancement of the disease with minimal side effects.

Getting the disease under control has allowed Sheen to return to work. He recently completely a still-untitled film inspired by the 9/11 terrorist attacks, starring alongside Whoopi Goldberg, Gina Gershon and Luis Guzmán.

"People still talk about the stuff I deal with," Sheen said of his personal struggles. "But [hopefully they'll] also talk about the work."