If its any consolation, suicide is a subject that all deep thinkers consider...either intelectually or literally. Superficial people don't normally consider it on any level. It is either conciously or subconsciously at the very core of recognizing your existence. Look at any school of philosophical thought...from existentialism/absurdism, nihilism, classical liberalism, judeo/christian, budhism, islamic, yadadadad...you name it...suicide is addressed. Some, Like Sartre suggest it is the oinly free choice man can make solely on his own, while others contend it is the ulimate affront to god/society/self.
Bottom line, its probably not entirely unhealthy to have such thoughts as long as you're still here to contemplate your own existence, purpose, choices. Well, at least most of you anyway
