why do people starve/harm themselves?

[United Ireland]

When I was younger,I used to cut myself.This was never a cry for help,nor was it suicidal.Self harming was my way of relieving the pressure that was building up in my head.I used to get some weird satisfaction from cutting myself and watching the blood flow to the ground below.
I was a victim of bullying when I was young and I did not get much support from school or home.I first had a noose around my neck at 12 years of age,but I could not understand why or what I was doing.I wanted to fight back and hurt those who were hurting me,but I was unable to do so.
I was suffering from depression from 12/13,but everyone just thought I was quiet and moody.I couldn't tell anyone what was going on for I couldn't understand it myself.
So from a young age I was pretty messed up and had no where to turn.I don't know why I started cutting myself but I can remember even now the relief that it gave me.It empowered me and handed me back control over my own body.Once I started cutting,the beatings never felt as bad again for I knew that I would be relieving myself of this pain later that day.I also started drinking alcohol at 14/15 and this too numbed the pain of life and also numbed the pain that I was inflicting on myself.
But cutting,solvent abuse,or any other form of self harm,can never be viewed as any logical solution to any problem that you may encounter.Whenever you use any form of self harm,you are realistically putting your life at risk.You mentally are not fully aware of what you are doing.It is not like you can read up on how to self harm safely.
I am lucky and blessed to be alive today.But I don't have to look far to see what damage I have done to myself.My arms,chest and wrists are all badly scared and this is probably 20 years since I last engaged in this insane practice.My kids have already seen the scars and I am dreading the day when they asked what happened.How do you explain self harming or suicide attempts to your own children?
I know why I self harmed and I can also understand why others do it.It is their bodies and they are free to do what they want.But I realise now that self harming never resolves anything,I was still been bullied and I was still suffering from a mental illness.The only person that you are damaging is yourself and you will have to live with them scars forever.