Finally went to the neurologist at the Headache Clinic here.
As referenced in the last entry, I've been having these ridiculously painful headaches.
They've basically gone away, but I went to the neurologist anyway, since it took a month and a half to get in.
Figured out what it was: "Low-pressure headache", caused by a periodically low level of CSF in my skull. It was mainly caused when I stood up quickly, or went from a prone position to standing -- major changes in body position and elevation.
Turns out that having a cup of coffee in the morning (a sorta big cup, but not a fuill pot, or anything) keeps it at bay, for me. when I was having the headaches super-often, I wasn't drinking much coffee; then the day I had some I didn't get a headache. Yay, data collection.
Likely issue is that the position change is allowing CSF to siphon down my shunt, and *pow*, GIANT HEADACHE that lasts 30-60 seconds and goes away as the CSF regulates itself.
Apparently the brain has no pain nerves, but the meninges do definitely have them, and the *bonk* of my brain into the bottom of my head may be the cause of the pain.
Recommendations were to wear a "Compressive Band" (one of those big velcro strap 'girdle' type things, I think) on my stomach area if I was going to be doing a bunch of up-and-down movements (playing with my son on the floor, etc), to maintain higher peritoneal pressure, a little. Also, a cup of coffee in the morning seems to keep the headaches at bay, and the neurologist had no issues with me having a normal amount of caffeine.
Simplest suggestion was to get up slightly slower. Seems to be working, overall.
Everything seems to be under control, now, but I figured I'd share an update. Thanks, y'all.
EDIT: also -- the previous headaches I had -- that were able to be solved with Diamox (acetazolimide) -- those were high-pressure headaches. Too much CSF. This was the other extreme.
Luckily, nobody wants to touch my shunt while it's still functioning correctly, and so... we watch things.