Terminal cancer sufferer Brittany Maynard, who planned to end her life on Saturday, has announced in a video that she has changed her mind.

The 29-year-old, who has moved with her husband and family to Oregon where assisted dying is legal and has campaigned for an extension of the laws to other US states, still plans to take prescribed legal drugs – but not yet.

Maynard was diagnosed with a brain tumour in January after suffering intense headaches and was initially given 10 years to live, a sentence she described as "devastating". However, in April doctors told her that her cancer had spread and that she had a life expectancy of only around six months. She decided to end her life before the illness became too painful and debilitating.

In her recent video, however, she says: "If November 2 comes and I'm still alive, I know that we'll still be just moving forward as a family out of love for each other and that that decision will come later."

She continues: "I still feel good enough and I still have enough joy and I still laugh and smile with my family and friends enough that it doesn't seem like the right time right now. But it will come, because I feel myself getting sicker. It's happening each week."

Her case has become a major controversy in the US and further afield, with some Christian groups offering support and urging her to reconsider, including a Facebook group set up by Boston priest Fr Tony Medeiros.

Others have warned of the risk to vulnerable people of relaxing laws on assisted dying. Maynard acknowledges in the video that she has been "hurt" by some of the comments, saying: "When people criticise me for not waiting longer, or, you know, whatever they've decided is best for me, it hurts, because really, I risk it every day, every day that I wake up."

She described a recent "terrifying" day when she had two seizures, saying: "I think sometimes people look at me and they think, 'Well, you don't look as sick as you say you are,' which hurts to hear, because when I'm having a seizure and I can't speak afterwards, I certainly feel as sick as I am."

She said that her greatest fear was taking too long about her choice: "The worst thing that could happen to me is that I wait too long because I'm trying to seize each day, but I somehow have my autonomy taken away from me by my disease because of the nature of my cancer."

Maynard has a 'bucket list' of things she wants to do before she dies and recently ticked off visiting the Grand Canyon. She wrote afterwards: "The Canyon was breathtakingly beautiful, and I was able to enjoy my time with the two things I love most: my family and nature."