Charlotte O'Brien's selfless final wish before she took her own life after being bullied at school - as her heartbreaking notes to her parents are revealed

The 12-year-old girl who took her own life after school bullying drove her to despair left notes for her parents urging them to share her story to help others.

Charlotte O'Brien, a Year 7 student at Santa Sabina College at Strathfield in Sydney 's inner-west, took her own life earlier this month after two years of misery where she said classmates were using confidential information to bully her relentlessly.

Her parents, Mat and Kelly, have now revealed the heartbreaking last notes left to them by their daughter including one that said: 'Mama, please share my story to raise awareness.'

Charlotte's parents found the notes left in small pink handwriting after their daughter had taken her life in the upstairs bedroom of the family home.

In other last messages, Charlotte told her parents to 'tell the school' about her suffering and that life was 'too hard'.

Another note referred to her adored infant brother Will.

'Please, Mama, live for Will because I can't anymore,' it said.

Charlotte learned she was going to be a big sister when her mother told her 17 months ago she was having a boy.

She didn't wish for anything for her birthday the following year because all she wanted was a sibling.

Mat and Kelly are still trying to process the numb shock of what has happened.

'The other thing that is troubling for us is that we had such a great last day with her,' Mat told the Daily Telegraph .

'I hadn't seen her that happy coming home from school in a long time.'

The parents said Charlotte was bubbling with happiness as she ate her favourite dish, creamy chicken pasta, for dinner and aced her maths homework getting every question right and doing 'little happy dances'.

She also baked banana bread and took a piece to her father, still in a joyously good mood.

After playing with her mum and little brother she said good night and 'literally skipped to the shower'.

'That's the last time we saw her alive and we could not understand what had happened,' Mat said.

Police told the couple that a person sometimes projects happiness before taking their own life because they believe they have settled on a solution to their probelms.

Charlotte's parents strongly reject that explanation.

Mat said the family had discussed their upcoming holiday, where Charlotte wanted to do a road trip, and even about what she and him would work on as maths problems the next day.

'This is not a girl that was planning on doing this. Something happened when she went to her bedroom,' Mat said.

Police are searching Charlotte's phone to see what messages she was receiving in her last hours.

Kelly remains wracked with guilt and regret and asked why her daughter didn't just come 'and get me to give her a hug that night?'

One thing that Kelly is adamant about is that she doesn't want people to say this had 'ruined their lives' because as devastating as the tragedy is 'she's what made us whole'.

The devastated mother said her daughter always felt 'big emotion'.

She described Charlotte as the 'sweetest, kindest, toughest, strongest little diva you've ever met in your life'.

Mat and Kelly believe Santa Sabrina College could have done more to stop the bullying inflicted on Charlottoe received.

Emails between Charlotte's mother and the school reveal Kelly believed the bullying was having 'severe ramifications' on her daughter's mental health.

Mat claimed other parents had also raised the 'toxic' culture of the school and that the school needed to just step in as adults and seperate children.

The grieving parents said schools across the country needed to take a 'zero tolerance' to bullying.

Kelly claimed after their GP called what was happening to Charlotte 'harassment' the school reject the term and said it was 'juvenile behaviour'.

At one point towards the end of Year 6, Kelly was shocked to see Charlotte's arm covered in scratches.

Charlotte claimed she was just itchy but her mother knew it was self-harm because she felt overwhelmed.

Kelly said on some days Charlotte would burst into tears as they approached school drop-off wailing that she 'had no friends', that everyone hated her and she was 'a monster'.

Santa Sabina College has defended its handling of bullying, saying their anti-bullying policy was available on their website.

'In the past week, I have been overwhelmed by the number of emails and messages from our families that talk about their children feeling safe and cared for at Santa Sabina College,' principal Paulina Skerman said.

She said parents 'objected to the portrayal of our College as failing to deal with matters that cause distress among our students'.

For confidential support call Lifeline 13 11 14 or Kids Helpline 1800 55 1800