It just seems impossible

I am a very cowardly person.  I am a waste of space, oxygen, food and my parents’ money. I have not and never will contribute anything good to society nor nature, and therefore I believe it preferable for both me and the world that I leave. I would also like to be an organ donor. I just hope my organs would be good enough for anyone due to my unhealthy lifestyle. Most of the time I agree with myself that suicide is the best thing to do. But I can’t, for the following reasons:

• Lack of courage. I am always afraid and worried of everything, and physical pain is not an exception.
• No immediate danger or extreme pain. At the expense of others, I have done all the selfish things I can to avoid what I fear. Everyday life isn’t a huge struggle, but it obviously will be later on.
• Guilt: I would kill myself for the harm it would do to my family, but oops, I already have.
• Human evolution: Not only humans, but any living organism. The current genes of any living thing are developed close to maximum efficiency to keep the body alive. Genes that are of convenience of killing oneself may appear through mutations, but would be unlikely to be passed down generations.
• Nothingness: I don’t believe in an afterlife or spirits. When I die, I would simply cease to exist, there would be nothing. Am I ready to approach that?
• Will to live: I do enjoy some aspects of life. But the effort to achieve them is not worth it.

Because of these reasons, I find it very unlikely I will ever succeed in committing suicide. But I find it equally unlikely I will succeed in anything else in life. What am I to do.