“That’s the challenge with mental illness: it’s really, really mysterious.”

Wynonna Juddis remembering her emotional last goodbye to late momNaomi Juddafterher death in April.

“That’s the challenge with mental illness: it’s really, really mysterious.”

Wynonna Judd and Naomi Judd attend the 2022 CMT Music Awards at Nashville Municipal Auditorium on April 11, 2022 in Nashville, Tennessee.

Wynonna and Naomi Judd.Jason Kempin/Getty Images

It’s also the hardest part for Wynonna to come to terms with following Naomi’s death.

“I didn’t.

That’s why it’s such a shock.”

“I feel her nudging me.

And sometimes, I laugh,” she said.

“And sometimes, I say, ‘I really miss you.

Why aren’t you here so we can argue?'”

Judd’s full interview will be broadcast onCBS Sunday Morningat 9 a.m.

ET on Sept. 25.