No, it does not keep me up at night even though you are correct about the very high likelihood of great world termoil; a nuclear armed Iran is even more terrifying. Like North Korea, once they have them, you can't take them away.
President Bush was an idiot actually attacking Iraq, he had already won with his other measures and 20% of the US and the rest of the world knew it. Why do I call him an idiot (stupid is over used)? Because he didn't read his history, or at least ignored it and listened to Dick Cheney and Don Rumsfeld instead, rather than Colin Powel. If he listened to Powel, Bush would have know, what happened to him and America was inevitable, it happened almost identically to the British after WW II when Iran was created.
The impending turmoil was not worth actually going to war in Iraq, it will be in Iran if all other measures fail and they are on the verge of developing "the bomb".