Adrenal gland.. Mostly relies on good neurochemistry, which relies on 2 things: good diet, and good gut health. Meaning: eat your yogurt (and bio flora for your tummy) and get all your amino acids! Good gut health = great digestion -> what you eat becomes good neurochem -> happiness and clarity.
Can you provide the source for this? I would like to read up.
Any other sources of knowledge to learn about neurosciences you would like to recommend would also be helpful.
There being no concise source on the matter of general health, diet, good neurochemistry, and mood, I can but offer a collection of disparate books:
Principles of Neuroscience (Kandel, Schwartz, Jessell) is a great textbook.
Emotional Intelligence (Bradberry)
Zen Mind, Beginner's Mind (Suzuki Roshi)
I also read a lot of personal experience vault essays on erowid.org (regarding "experimental medicine," for lack of better terminology)
Burn out is not really something physical. You probably need some rest, but it is less than what you think (measured in days). Your own mind is dissatisfied with some of what you are doing and it is raising red flags. You need to figure out what is it.
Do you like writing software? This is the first question. If you do, keep going, but you need to focus on something else. Maybe a slightly different industry, or smaller companies, or even something on your own.
I agree with the comments about college. You don't know what you are missing out until you do. It's great that you are self taught, which is an important skill for college.
There are a few reasons to enroll. You are unlikely to be implementing data structures in your day job. However, some algorithms are very hard to understand, and it forces your brain to work really hard to crack them. Then algorithmic problems at work become rather trivial. And the remaining non-trivial can be reduced to one of the problems you already know.
Second, there's the exchange of ideas. You'll notice that many billionaires are college dropouts. Meaning that they did enroll and took classes, and decided to quit because they found a big opportunity. Odds are you are going to leave college in debt instead of a billionaire, but you'll leave with knowledge and connections, which are worth more.
And of course, your CV will be better for it.