16 and Pregnant's Whitney Purvis Speaks Out in First Interview After Son's Death at 16: ‘I Can’t Imagine Going On’ (Exclusive)

The '16 and Pregnant' alum tells PEOPLE it feels like time has been "standing still" following her son's death

Whitney Purvis is opening up for the first time about the days since her teenage son's tragic death.

During an exclusive conversation with PEOPLE, the 16 and Pregnant alum, 33, shared new details about her son Weston's death on Monday, June 2, and how the former reality star has been coping with the loss. Purvis, who shares her two children with ex Weston Gosa Sr., says that she feels like time has been "standing still, just frozen" since learning the news.

"I can't distract myself," she tells PEOPLE. "It's going through my mind constantly. I hate to even pick up my phone."

"When I'm not crying, I'm just staring at the ceiling," she continues through tears. "I never wanted to go through something like this. I mean, I know no one does, but you never think it'll happen to you, and I just can't even imagine a future now. I can't imagine going on after this."

Purvis explains that she was pulling into a parking lot for a class she was taking before she received a call from Weston's father. Since they were in the midst of a disagreement, she didn't pick up at first. However, when he called again and sent a "911" text, Purvis says she knew something was wrong.

"When I answered the phone, I could hear him crying before he spoke, and I knew it was going to be bad, and he told me, and I was just in shock," she recalls. "He told me everything he knew at that time, and that he would call me back, and I just pulled out of the parking lot and drove home and just screamed in my car, just screamed to the top of my lungs."

"I didn't want it to be real," Purvis adds. "I didn't understand what happened."

After calling her mom to deliver the news, Purvis called back Gosa Sr. to request that an autopsy be done on their son. While the family doesn't know exactly what caused Weston's death, Purvis says that when Gosa Sr. looked at footage from his house cameras, the teen could be seen getting up all night long and struggling to get a good night's sleep.

"Big Weston said he came in Little Weston's bedroom at 7 in the morning to wake him up, and he wouldn't wake up," she explains. "They called 911, and he did CPR until the ambulance got there, and they pronounced him dead at the hospital."

Since receiving the news about her son, Purvis tells PEOPLE that she's been by herself and has wanted to be alone as she processes everything that has happened.

"I've kind of wanted to be alone just because I have a hard time just talking to people," she says. "I just go through so many emotions, like being sad, being mad. It's just been really, really rough. I've never cried this hard in my life, to where my eyeballs are swollen."

Purvis and Gosa Sr. also share son River, whom they welcomed together in 2014. The Teen Mom alum tells PEOPLE that her younger son doesn't quite understand the situation.

"River doesn't understand it," she admits. "River has autism, and I don't think he quite understands what's happening."

Since the news of Weston's death, Purvis has received an outpouring of love and support from relatives, friends and those who've followed Purvis' story since she was on 16 and Pregnant. From messages on social media to donations to the Spotfund that Weston's stepmom, Amy Gosa, started to raise money for the funeral and headstone, Purvis says she's seen a lot of messages that "make me feel better."

"It's nice to see people care and care about him," she shares. "I'm very grateful for the support people have been giving me and giving his father and stepmom."

"I think it's very sweet, the people who have donated, because we would really like to bury him instead of cremating, and get him a nice headstone, and so the donations mean so much," she adds. "I'm very grateful for the support."

As Purvis continues to mourn the loss of her son, she keeps sweet memories, like special mother-son outings and their shared sense of humor, in her mind. The proud mom says that Weston loved playing with action figures and was really into computers and video games. She said he had dreams of becoming a YouTuber one day, and was ultimately just a "good person" with an "old soul."

"He was shy. He had an old soul. He loved animals and always made a friend wherever he went, " she says. "He was a really kind boy. He was a really good boy, and he was so funny and handsome. He was such a good person."

"He was just a perfect kid," she adds. "You just didn't have any trouble out of him at all. He was smart, and he was super bashful, and a great big brother."