Teen Mom OG's Mackenzie McKee on Her Final Moments with Her Late Mom: 'We Held Her Until the End'

Mackenzie McKee is saying a final goodbye to her mom, Angie Douthit.

Tuesday night's Teen Mom OG features McKee's final weeks with her mother before she died in December, after a nearly two-year battle with cancer. Ahead of the emotional episode, McKee opens up to PEOPLE about Douthit's death — and how she plans to carry on her mom's legacy.

"I miss her every day. I'm doing a lot right now to get closure," McKee tells PEOPLE. "The fact that the world gets to see who my mom was and that so many people care, it does help."

In August, Douthit revealed on Teen Mom OG that doctors had given her six months to live. Three days before her death, Douthit announced she had decided to stop treatment because the cancer in her liver and brain had spread.

McKee says she didn't leave her mom's side at the hospital until she took her "last breath."

"She left a very powerful impact. She spent her whole life loving hard and loving no matter what. She was always by your side, everything you went through, good or bad," she says. "And then, in the end, it was her turn to be surrounded by the people who love her. We were there for her and we didn't leave."

"We slept there, we stayed up all night," she adds. "And we held her until the end. She had us holding her until her last breath."

Nearly five months later, McKee says she's still struggling to come to terms with her mom's death but is doing her best to live in a way that would make Douthit proud.

"I'm going through a dark time and dealing with a lot of depression and anxiety. So I'm going through counseling, fixing myself, one day at a time," she says. "But I have changed so much. I just want to always do the right thing."

Teen Mom OG airs Tuesdays at 8 p.m. ET on MTV.