Don't distress yourself. I don't think that the majority of the people here can ctb too, you have to fight the society's constant abjuring of the privilege to ctb because of the present anti-suicide ways. In addition, you also have to fight SI which is very hard to defeat because of thousands of years of evolution, the body evolved to prevent anything from killing it, even if your mind doesn't want it. You can't do anything about it and lots of people, including you are disappointed and feel very incompetent because of it. Its not your fault, try not to be so hard on yourself. You'll succeed someday, i know it. I send you my best regards.