Holding out for 'whatever' has lost its appeal

Why is love and security so important to me? I don't really know. But I wish it wasn't. I wish I could just acccept my circumstance as my destiny and be content with just living until I die? I just don't have the patience anymore. So if I'm living a life that I do not enjoy...why live it at all? I know most people won't "get" this way of thinking, but if I'm so unhappy and just want to be free of this human existance why shouldn't I be able to just go. There are tons of people out there who could benefit from my freedom from this wretched shell. Its my intention to donate all of my organs, tissue, blood, etc. Is it so crazy to think this way? If we hate our jobs we eventually quit them right? Why can't I just quit this? Oh and by the way me "quitting' my life will not affect anyone else. I have no kids, parents, or spouse. I can certainly be replaced at work also.
I'm just so very tired. One failure after the next is hard enough when you have something to fall back on like family, a home, etc. but when you have nothing to go home to when times get rough its twice as hard and I don't want a hard life anymore.