the earth has enough resources to last at least another 3 billion years, scientists have proven it. it is a given guarantee that we will all die well before the world ends. that means we do not have to die prematurely, you do not have to die before your body gives up the fight. the only people who will die on the 21st are those who have been chosen by God to reside in Heaven and once he chooses you there is very little yu can do to prevent it.

if you still feel the need to kill yourself, please do two things first
1/ think about how the person who finds your dead body will feel, how the experience will affect them for the rest of their lives, bear in mind it could be a child who finds you, would you like a child you care about to find a dead body? there is no definite way of dying in the knowledge that your body will never be discovered, no matter what you do

and 2/ tell someone close to you what you plan to do 28 hours before you do it stressing the fact you are going to kill yourself five times