My rucksack is packed, my walking boots are waiting by the front door and Boots is £51.53 better off, thanks to a last-minute online spree to stock up on blister plasters, first-aid kits and anti-histamine.

In three days’ time my 60km journey across the South Downs will have begun, though I’m not too sure what to make of it.

Last Sunday, Mario and I walked 30km in the pouring rain, stopping only three times: once for a quick sandwich, once to pull on our waterproofs and once to take them off again. No matter how tough it’s going to be by the evening, I think I’m up to the physical challenge.

What I’m less sure about is the emotional side of it all because ever since I wrote an article for the Telegraph last week, my head is a scramble of thoughts, as if my emotions have been put into a blender and shaken up. Instead of feeling calm, I’m strangely unsettled.

A week of waiting and doing nothing is a part of that. Back on February 1, I was a gym novice who tentatively took out a three-month membership in order to reach May 11 with optimal fitness. That expired last Wednesday and I haven’t been to the gym since in a bid to give my body the rest it needs.

Sitting at home with my feet up only adds to my feelings of unease. The reason I’m doing this walk, after all, is because my brother killed himself and, on Saturday, I know there will be no escaping that fact. While I’m walking through the woods or up the steep hills, I will be acutely aware that his suicide - and my need to make sense of it - is what made me decide to take up the Big Em and M Challenge in the first place.

I’ve come a long way since last June when I paid my registration fees and started writing this blog – both in terms of fitness and where I emotionally. It’s definitely true that over the past 11 months I’ve walked and written my way through my grief, even if I’m not quite out the other side.

Except this hasn’t only been about me. I hoped I’d be able to raise £2,000 for Winston’s Wish, the UK’s leading childhood bereavement charity, and at £1635 I’m almost there. What has got me through the past four years is hope and optimism and that holds true now because I really do believe I can pull in the outstanding £365 before I finally cross the finish line in the dark on Saturday evening.

But there’s one thing I failed to take into account and which still astounds me now and that’s the impact that I’ve had on other people, some of whom are good friends, some of whom I barely know and some of whom are complete strangers.

People have emailed or Facebooked me to share their stories. The ones which have affected me the most are those who have donated and said my brother’s story could so easily have been theirs. It’s a reminder that the fragility of life is all around us and that dealing with mental health needs to be as open as talking about cancer.

Others have thanked me for trying to break the taboo of suicide or for bringing childhood bereavement to the fore, even if there’s still an incredibly long way to go. I’ve never revealed the names of my nieces and nephew in print and I believe that’s a shame, in as much as they are three tough survivors of repeated bereavement: not only have they lost their dad, they’ve lost their extended family, their school and a country and culture they were comfortable and familiar with. It’s wrong that their identities should be concealed because, in some way, that pushes the stigma of suicide and childhood grief even deeper.

At first I was unsure about my writing about my situation as a suicide survivor, afraid that I would come across as a whinger and someone who was so stuck in the past, they couldn’t move forward.

Indeed, there have been countless times where I’ve burst into tears as I’ve described certain scenes, such as when I wrote about my nieces imputing the family birthdays into my iphone or when I blogged about my anger on my Matt’s birthday. It hasn’t magically got any easier, either. When I tapped out the 1,300 words for the Telegraph piece last week, I cried noisily throughout.

However, I’ve now seen my voice is louder than I thought, making me realise that I have made a difference and can continue to do so. It may not have been my original intention but life has a habit of taking us on twists and turns and far from the path we had originally chosen.

So where I go from here, I’m not too sure. Once I’ve celebrated with a slap-up meal, eased my aching muscles and emailed everyone to thank them for donating, I’ll quietly wait for the answer.

But while I’m doing so, I’ll be back in the gym, my membership renewed for another year.

Emma Bird is walking 60km across the South Downs, in West Sussex, on Saturday, May 11 in aid of childhood bereavement charity Winston's Wish. To donate, please click here.