What an aggressive tone ! If course we will say "Don't Do it" because we don't suffer at present from the distorting and biasing twisting of your perceptions of life and your options in it. We know that there are options for a more satisfying life available which you have not yet taken ; we dont think it makes sense to insist on taking a permanent and irreversible step for what IS, hoever much you may have managed to hide the fact from yourself, a temporary and remediable situation. Yes, you are right that there is a high risk of rendering yourself badly damages and much more miserable for the rest of what could be a very long and horrid life, by a failed attempt, and there IS no fool-proof method. I have seen people survive attempts against enormous odds, and I have seen people maimed for life or dead from trivial attempts which they used as manipulative methods and were certain they would survive unharmed.
Obviously there can be no "good websites" which would provide such information--- if they did, they couldn't be "good", only wickedly irresponsible and mischievous.
DO call Lifeline, and more urgently, call your psychiatrist, or a good local GP, orgo to the casualty dept of the best hospital near you, explain exactly how you are feeling, and ask for the best advice and help. Do you think you deserve less than that ?