I watched a great animated movie last night, "All Star: Superman." In it, Lois Lane visits Superman at his fortress of solitude for the first time but disappointingly she starts acting bizarre. She becomes highly nervous and begins to assume that Superman brought her there to experiment on her. After planning frantically to defend herself, she grabs a kryptonite laser from his arsenal and blasts him with it.
It turns out that she was exposed to some chemicals that increased activity in her amygdala. At that point, it all made sense to me. Even though Lois Lane is kind and thoughtful, she has the potential to become paranoid when severely stressed. She didn't have a good reason to suspect Superman of foul play, but when our amygdala is activated, we often trust it unquestioningly. We do this because it is so often right. The amygdala has a mind of its own. It unconsciously listens to many other brain areas and takes cues from the environment about when to be scared. We accept its messages as a type of foreboading intuition.
When activity in the amygdala increases, and the adrenal glands begin to release adrenaline and cortisol, the brain becomes primed for negative thinking. It is like your brain is retuned to perceive things as troublesome or upsetting. This is the opposite of a manic episode where someone with mania might perceive everything as a happy, lucky coincidence. A friend of mine who has experienced mania told me that for two days it felt like all of the cars of the freeway moved to let him through, like everyone was agreeable and like everything was going his way. When I start to feel that everything is going poorly I try to remember this - that neurochemicals can paint over reality.
I have noticed recently, that if one thing stresses me out, I am much more likely to get stressed out about other, completely unrelated things. I might get upset about an unfortunate circumstance and then wear cynical glasses for a full hour afterwards. One could say that this "displaced" negative thinking is not logical. It may be evolutionarily logical to be prepared for the worst during bad times, but from a modern, practical perspective it is illogical to generalize anxiety to whatever your mind turns to.
Remember, cortisol is high in the morning, so don't give morning stressors the attention that they feel they should be given. Also, remember Lois Lane, and make sure that one unfortunate circumstance doesn't lead to a domino effect of paranoia. Nowadays, I try to notice when I carry negativity over, from one thought to another. When I can notice it I try to tell myself that the negativity may feel valid and intense but it is probably just residual and misattributed emotion.