Charlotte Baron, 14, also penned a series of drawings depicting her self harming and posted entries saying she didn't like the size of her body.
One heartbreaking entry in the notebook told of an incident where she wished she had died after being admitted to hospital following a drinking bout over the Christmas holidays.
It read: 'I almost died - I was so close. I just wanted to forget everything. I just wanted to die. I was so f****** close why did they have to save me, why, I don't want to be here. Why won't they just let me die.'
In February last year Charlotte, from Rochdale, Greater Manchester, was found hanged in her wardrobe by her older brother Tyler, 20, who had been looking for a phone charger.
Police discovered she had sent a last text to a friend reading: "What the f*** is going on with me, I'm such a f****** wimp. F***.'
The hearing in Heywood was told Charlotte, who attended St Cuthberts Roman Catholic High School in Rochdale, appeared to be a happy girl and was close to her grandmother but she began self harming when she was 12.
During one incident, the teenager was admitted to a hospital A&E department after an overdose of paracetamol and was referred to mental healthcare professionals who gave her counselling sessions.
She was also badly affected by her grandmother being diagnosed with terminal cancer.
Charlotte's mother Veronica Kilbride, a 42-year old mother of five said: "I found out that she was self harming at 12.
"I had seen marks on her arms, and she denied it at first but then eventually admitted it. She was growing at a rapid rate and had body issues like most teenagers do.
"I don't know how often it happened, but she said it hadn't been going on that long. I let my mum talk to her because had been a self harmer and Charlotte seemed to get better after that.
"The scars on her arms had cleared up but I didn't realise she was cutting her legs because she always wore leggings and shorts and they were hidden.
"After she died I saw the pictures in the diary of the drawings of the cuts on her legs.
"When she took the overdose, my mum found her and went to the hospital with her. She came home the next day.
"I spoke to her about it when she came back from hospital but she said she didn't want to talk about it and I didn't want to get her upset or for her to upset herself.
"My mother said to her that she was attention seeking but I never said that. We cuddled after because she wasn't herself and she wasn't right. I didn't want to press her too much.
"Charlotte was given too much freedom and I let her hang around too much with her friends because she didn't want to see her grandma deteriorate in the way that she was.
"She was quite a popular girl and socialised as teens do. But on December 29 she was found unconscious in a field when she had been drinking amaretto and vodka and she passed out and one of her friends came to get me and Tyler.
"She was unconscious for quite a while and when she did come round she was rambling saying how sorry she was. I was just happy to see her wake up.
"I thought that the drinking was the type of thing that teenagers do but that was a cry for help and I didn't see that.
"On the day she died it was half term and she was doodling on her books and I thought that she was just having a lazy day. I had seen her laid in bed reading and I assumed she was asleep because she didn't say anything to me.
"Then Tyler went up to her room and was screaming down to me and my partner. I did CPR on her but she was already gone."
Tyler, 20, said in a statement: "Charlotte was a happy kid and nothing seemed to be wrong with her.
"I would hear Charlotte when she was in her room because it was below mine so I could hear her laughing with her friends and listening to her music.
"Charlotte didn't go round telling everyone about her private life and she was generally a private person. The week she died Charlotte seemed completely normal."
Det Insp Andrew Butterworth told the inquest: "A black notebook was found entitled 'drawing diary' and signed Charlotte Baron. There was a number of drawings in there. The drawing on the first page was a hand with writing outside it.
"The hand had self harm marks in the arms and the words described Charlotte talking about harming herself, and as you go through the book talking about how she doesn't like the size of her body etc, that she's overweight and alludes to being depressed and not happy.
"There is a date on one drawing on page 3, which is the 30 December which appears to be a reference to the day after she was intoxicated. There is an image of a bottle and it says. 'So today is the 30th tomorrow is New Years Eve, yesterday I overdrank and ended up in hospital again.
"I almost died. I was so close I just wanted to forget everything. I just wanted to die. I was so f***ing close why did they have to save me, why, I don't want to be here. Why won't they just let me die.'
"The only drawings after that were of an eye and a hand with no text. The last message sent by Charlotte was to a friend of hers saying 'What the f*** is going on with me, I'm such a f****** wimp. F***.'
"During the day there were texts regarding her feeling depressed and nobody understanding her."
The hearing continues.
If you’re struggling to cope with mental health issues here are some of the ways you can access help.
Samaritans (116 123) operates a 24-hour service available every day of the year. If you prefer to write down how you’re feeling, or if you’re worried about being overheard on the phone, you can email Samaritans at email@example.com.