Damien,
Can I call you Dimmy? You know, the whole Exorcist thing? Nevermind.
First off, peak oil is most definately not a reason to kill yourself. There are loads of other reason to commit suicide. This one, however, is not. Besides that, it's selfish. An old schoolmate of mine hanged himself a few years ago. It did terrible things to his family and friends. You would probably inflict much guilt on your parents, and maybe even you brother. I've thought of it many a time in my life. I still do today. But, I don't think I would ever do it. For one, I wouldn't want my family left wondering whether they were responsible or whether they could have done something to stop it. As much of a bastard as I am, I am not devoid of morality. Also, I wouldn't want a bunch of assholes who didn't give two shits about me when I was alive showing up at my funeral.
That bond you have with your brother is a great gift. It's the kind of thing that can transcend even the worst of what peak oil and the other "coming catastrophes" have to offer. It should certainly motivate you to live a long life.
Since learning of peak oil, I have been, in sequential order, extremely depressed, motivated, furious, motivated, and finally, indifferent. Why was I depressed/angry?
Although I lean towards the negative side on how this will all turn out, I really cannot picture what the world will be like in 15-20 years. One thing I know, however, is that I really don't care if I survive through it. Sure, I would rather not starve to death. But deep down, even facing that prospect, I can't find a reason why I should want to make it through this (i.e., your bond with your brother). Not good. Not good at all.
I have become the most cynical s.o.b. I know of. Hell, I barely believe in love. Luckily, I can hide it rather well with a healthy sense of humor. I don't ever see myself shaking of these feelings. I wouldn't allow it.
Be glad that you have a special relationship with your brother. Use it as motivation to get through your current state. Not everyone has such a reason to make it through tough times.
Get some sleep. You'll get over this panic attack. Everyone has

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