Thanks for being super open about your struggles with drugs. There are users on here that have had similar experiences with addiction. Have you heard of an organisation called Turning Point - they are focused on drug and alcohol addiction support and can provide more specialised advice for you.
Drug addiction can be so difficult to beat. I think it's great that you want to stop it though.
Have you considered talking to any professionals about it? Your GP might be able to refer you to services that can help you in your local area. This helpline might also be useful. They might be able to give you some advice.