Specifically, cortisol normally has a significant peak in the morning with waking, but I don't have that. My cortisol levels throughout the day are about flat, so normal for the evening, but not elevated in the morning. According to my doctor, this isn't too unusual, and should adjust up to normal levels after some months of supplementation. I just started supplements two weeks ago, and I'm definitely far more awake during the day and have a much easier time starting the day, but I haven't noticed any other significant changes, so I don't know anything else attributable to this. The only other changes I've noticed have been pretty minor, like an easier time exercising, and maybe a bit more irritable.

Chiming in: cortisol IS "the stress hormone" but "stress" in the body sense is not the same thing as we think of "stress" in our daily lives.

With my chronic fatigue syndrome, there was a period where I had signs of "adrenal fatigue." My body would not produce sufficient cortisol and it REALLY showed. Symptoms included difficulty with physical activity, e.g. standing up or climbing stairs, an overwhelming agoraphobic-in-a-mosh-pit feeling in my head when faced with making any kind of decision, weighing facts, or even too much sensory input (e.g. talking to me while touching me or touching me while I tried to tie my shoes), etc. I would jerk away and have a sobbing meltdown because I couldn't cope. Among people with adrenal/cortisol issues, that is called a "crash".

So I have learned that sensory input, thinking, information processing, etc., are all types of stress on the system. Cortisol is required for the body and brain to "rise to the challenge" of almost every kind of effort, not just "I'm freaking out" type stress. In the case of the OP, staying awake was clearly a challenge his body could not rise to because it had insufficient cortisol on hand.