But she's made her peace with the idea, saying she's only 33 years old and "I still have a little bit of time on my side".
Setbacks like this have provided a learning curve for Street, who also planned on doing a marathon until her doctor laughed in her face - "I realised then that perhaps I do need to remember to slow down a bit and look after myself," she said.
"Right after I was diagnosed, I thought, 'I just don't care about the small stuff anymore - I'm going to do whatever I like and whatever makes me happy'. But to be honest, it's not realistic to live like that.
"Suddenly you find you've gone back to your everyday life and you realise that the small things do matter. I'm still looking after two little children and going to the park, getting coffees, going to work each day. But that's what makes up my life and makes it rich. I am happy and so thankful for that."