There are reasons for pessimism, but not the reasons you think. The scary story you're telling yourself is hard times in your past plus static of your intelligence trying to cooperate with your fear. Find the optimism you can believe in most, even if that is only a little belief, and move from it and to it. Sneak around the realistic causes for pessimism by being yourself. Your actual self, product of all that long DNA, is a very powerful part of reality, too. Walk as yourself, and you'll be walking far from the real reasons for pessimism which will just have to lump it as you reach a better place catalyzed into existence by the powerful chemical, you.