Mrs Pelham suffered from post-natal depression after her first daughter Isabelle was born in 2009 and again after she gave birth to Abigail two years later.
"I experienced difficulties post-birth with bonding and found it hard to cope with what was supposed to be a joyous time," she said. "I had feelings of guilt and frustration, it made me wonder whether I was a good mother.
"I was yelling at a little baby then feeling guilty; I knew logically it was not the way to react."
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READ NOWMrs Pelham said her illness intensified after the birth of her second daughter but she finally sought help and was diagnosed with post-natal depression.
"Going on medication gave me the chance to unwind," she said.
Mrs Pelham started taking part in community races two years ago, running while pushing her daughters in a pram.
"It has been a long struggle but I am finally beginning to see the light at the end of the tunnel and running has been my saviour," she said.
She will take part in the City to Surf marathon on August 30 while pushing four-year-old Abigail to raise money and awareness for The Black Dog Institute.
"I have become passionate about drawing attention to mental health issues through my own experience and decided to take this one step further and fundraise for the institute," she said.
"You never expect it's going to happen to you and knowing other people are experiencing the same thing is really encouraging.
"I want others to know it can happen and it's nothing to be embarrassed about."
She is also starting a group for northern suburbs mothers suffering from similar mental health issues. "It will be a supportive environment, where people can come without feeling judged," she said.
"I want them to feel like they're not alone, they're not the only one who hasn't bonded with your child or fallen in love with your baby straight away. Seeking help is the biggest thing because it's not you, it's actually something going on in your brain."
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For more information about the mother's group, email lizpelham@live.com.au.