United Kingdom, April 19 -- Teddi Mellencamp is suffering "debilitating pain" as she worries about the worst case scenario of her cancer diagnosis.

The 43-year-old reality star has stage IV melanoma, which has spread to her brain and lungs, and she admitted her fears about missing out on special moments in the lives of the three children she shares with estranged husband Edwin Arroyave.

Speaking to 'Entertainment Tonight', Teddi said: "I'm like, I don't think that you understand like the debilitating pain that I feel some days thinking about the fact that like my kids. My kids are young. I mean, I remember one day in the hospital, I was like, 'I feel like today might be Dove's birthday,' and Edwin's like, 'It is. It's her party today th...