I've been thinking about the sleep/wake cycle, alertness, endogenous neurotransmitters etc.

It's winter time here and the sunlight is at an all time low.
Seasonal Affective Disorder is apparently caused by low-light levels.
I assume this disturbs the sleep cycles and therefore messes up the body's neurochemical balances.
Also, not to mention artificial light from tablets, computers, tvs, phones.
When you check your phone late at night.
The human mind probably has trouble adapting to this un-natural light source at times when it expects little-no light.
The wiki says it it is common and I suspect more people may be "suffering" from it.

http://en.wikipedia.org/...sonal_affective_disorder

"Treatments for classic (winter-based) seasonal affective disorder include light therapy, medication, ionized-air administration,[22] cognitive-behavioral therapy and carefully timed supplementation[23] of the hormone melatonin.[24]"

I just set up a super bright light on my desk and I noticed more alertness and positive feelings within minutes.
Also I've been on a poor sleep schedule so tonight I will take melatonin and try to get a reasonable sleep. (8 hours) (11PM-7AM)

Any thoughts on this?

I'm just worried about my eyes. (They don't hurt yet)

Why are you worried about your eyes? Think i missed something.

I set up a VERY bright light next to my desk
It's the kind you would hang on the ceiling, the tubular bright white lights.