She continued, "This is the reality of how I have looked every day for 9 months, debilitated by nausea, bedridden and at times hospitalised. The easiest way of describing HG is ‘severe morning sickness’. But as fellow sufferer @amyschumer said 'comparing HG to morning sickness is like having an arrow through your skull and saying it's like a minor headache'.
"It is a terribly isolating journey of chronic nausea with no relief. I have felt poisoned every second of this pregnancy, it’s like having gastro every minute, every hour of every day for nine months. It is possibly the greatest mental and physical challenge of my life.
"And the only way through it is my daughter’s smiling face every day, the support of incredible friends and family, and knowing that each day I’m getting closer to this much wanted, longed-for baby angel 👼🏼 So for any other sufferers out there I hear you, I feel you and I know what you’re going through."
Box gave birth to Trixie, whose father is former Ironman Grant Kenny, in 2013.
Announcing her second pregnancy via Instagram last month, Fifi shared a sweet video of herself and daughter Trixie revealing the news. Box revealed in her post that she was expecting her child after undergoing IVF with an anonymous sperm donor.
“After a series of egg retrievals and freezing, last year I started the process to become pregnant via an anonymous donor,” she said. “I know the value of this miracle because I have seen first hand the heartbreak, tears and sacrifices so many women and couples suffer on their IVF journeys and my heart goes out to those who are facing that pain and struggle,” Box wrote in her emotional post.
WATCH: Fifi Box Reveals She's Pregnant To Her Daughter Trixie.