What you describe for headaches sounds like the early stages and/or mild case of what I have -- non-24 sleep wake disorder. This is particularly so given the things you've said about staying up odd hours to actually get things done.
I have an extreme case -- and a rare one at that since I'm male and sighted -- in that my daily 'period' is up at 26 hours. If I do not live a 26 hour day sleeping roughly an extra hour and staying awake an extra hour, and instead try to maintain a 24 hour day, well...
Days 1-5 -- progressively worse headaches, nausea, irritability, as the days wear on it increasingly becomes like being jet lagged. By day three it feels like I've not slept a wink no matter if I get a good solid 9 hours or more. Likewise body temperature regulation starts to go haywire where I constantly feel hot even in sub-freezing temperatures.
Days 6-7 -- early symptomology of sleep deprivation regardless of time slept/awake, including nausea, inability to concentrate on even the simplest of tasks, screwed up equilibrium making it dangerous to even stand, and rather oddly screwing up routine tasks like trying to brush your teeth with the wrong side of the brush, or pouring your OJ into your cereal and milk into the glass. (that last part is called apraxia). Headaches reach the point where I will bolt awake in the middle of the night screaming in agony. A constant low drone of 'voices' like standing in a crowd even in the middle of the night begins to appear.
Days 8 onwards, full on hallucinations of constant voices, things moving in my peripheral vision, varying degrees of paranoia and depression. There is also this awkward sensation of feeling like watching and hearing the world from deep underwater.
It goes downhill from there.
For YEARS I went untreated on this, having "good weeks" and "bad weeks" where "sleeping Saturday away" acted as a reset of sorts so I rarely if ever saw the day 6/later symptoms. (though I had the full gamut as a toddler) Then I got misdiagnosed with endless medications (mostly for bi-polar and anti-epileptics) that only made things worse thrown at it, until august 2002 when I had a complete mental collapse -- I went from office executive in Boston, to owning my own successful whitebox mom & pop PC builder and networking install company, to not even being able to hold down a third shift cashier job and landing in a homeless shelter as the crazy guy yelling at people on street corners in a period of under four years.
Which is when I FINALLY (fifteen years ago) had a diagnosis that helped. Non-24. One sleep study later, a month of living 26 hour days, and I was right as rain again -- in fact I was in the best mental and emotional shape of my entire LIFE. ALL my recurring problems right back to my childhood were a result of trying to live a 24 hour day like every other "good little drone".
Took me a long time to crawl out of that hole.
Though now thanks to one of those misdiagnosis and incorrect medications (Neurontin/Gabapentin) I have a "medication induced Parkinsonism" that my doctor finally just said "screw it, we're calling it Parkinson's so you can at least get the proper help". Hence why I'm on a mix of Keppra to keep the seizures under control, and Seroquel to help regulate my sleep and alleviate some of the visual oddities like seeing random movement in my peripheral vision -- a symptom of BOTH Parkinson's AND non-24.
The headaches still occur infrequently six or seven times a month, and I'm on the legal limit of sumatriptan to help when it is REALLY bad. Fun medication as it pimp slaps migraines like nobody's business, but has unusual side effects like sulfhemoglobinemia; green blood from a presence of too much sulfhemoglobin in the bloodstream. That's why you can only get NINE PILLS A MONTH of it. Needless to say I horde them since there are months where I NEED them two or even three days a week. Said months are called "July" and "August".
The normal treatment for non-24, "light therapy" doesn't work worth a damn since I'm adversely photo-reactive (not uncommon with Parkinson's apparently) with reverse seasonal effective disorder (summer makes me sick). Likewise there's a new medication that's supposed to help with non-24, but ALL it does is help you maintain the normal 24 hour sleep cycle, and NOT help you with the bad symptoms that occur when you do so. (the med is meant for non-sighted patients. 70%+ of the blind have non-24 and only around 1% of them suffer the symptoms sighted patients endure)
... and even for all the treatments, at least once a month I'll have a day where if I don't medicate myself to sleep, I'll be awake 70 hours plus, followed by sleeping 40+ hours, barely even being able to wake up long enough to deal with when Gaea beckons. Hence the Seroquel nightly is a much needed precaution.
Which is why I'll NEVER be able to work a normal 9 to 5 job ever again, and am forced to freelance. I'm also FORCED to work against doctors orders since medications and treatments are expensive, and SSDI + Medicare + Medicaid only covers a fraction of what it costs for me to even stay alive, much less keep a roof over my head.
Well that and I keep working because sitting around with my thumb up my arse was never my strong suit. I don't know how most "disabled" people do it!
... and all that's before we talk about how the above ALSO negatively impacts the pancreas, giving me one of the worst cases of Type 2 diabetes you can imagine, which is why I'm on Glipizide, Tresiba, Trulicity, and Humalog -- which combined with a 160 carb a day diet I still struggle to keep my fasting's below 200. Of course high blood sugars can ALSO trigger migraines and seizures so... fun times.
Good thing I've been clean and sober since 1993, or with all these medications I'd need a liver too!
This condition being one of the 'invisible' ones is very hard to get people to even accept. "Oh but you LOOK fine" -- next person that says that to me gets my boots so far up their rump they'll be flossing with my laces. It can be debilitating and crippling, but worse SO many people will tell me "oh just deal with it" or "you made that up". In fact it was only codified in 1979, and wasn't accepted by the U.S. National Center for Health Statistics as an actual recognized disease until 2005. This means most DOCTORS have never even heard of it, and those that have certainly don't seem to have heard that sighted people can get it too.
The idea that for me, right now, 6AM local time is 8PM on my schedule, and that tomorrow it will be 10PM utterly confuses the 'normals'. My schedule shifts two hours a day, or I go bonkers... and every other week I am NOT available during daylight hours.