The campaigner, 40, spoke about how she was feeling after doctors told her there was nothing else they could do for her.
She was diagnosed with bowel cancer in 2016 and began documenting her journey with treatments on social media, which led to a huge following.
Dame Deborah – who last month was honoured with a damehood from the Duke of Cambridge – has raised more than £6.6 million for Cancer Research UK, Bowel Cancer UK and the Royal Marsden Cancer Charity through her Bowelbabe fund on Just Giving.
The podcaster set herself an initial target of £250,000 and has received donations from a huge number of supporters.
Dame Deborah said she felt “angry” this week in particular, but added that she gets joy at doing things such as helping her family cook and getting ready in the morning.
She told The Sun: “Dying is really hard. I’ve been consumed by anger this week, in all honesty, I’ve been a real bitch.
“I keep shouting at people and pushing them away. I’m angry at what’s happening to me. I don’t want to die.”
“There’s no right or wrong way to die,” she says. “I’m still doing this my way. I’m frustrated with my situation because I don’t want to die. I don’t think I will ever really accept it.
“I don’t really believe that it’s happening. It all feels like a horrible joke. Watching the demise of my body is really, really sad.”
She added that death is “life’s last taboo” and she hopes that by talking about it she brings comfort to others.
Earlier this week, Dame Deborah held a sleepover with her friends and family, which she said “put such a smile to my face”.