the way it's been happening for i guess a few years, now, is that it starts with this blurred vision that is sort of like the climax of a mushroom trip. this is referred to as the "aura", but a mushroom trip is really the only way i know how to explain it - and it's actually extremely accurate, with the escherian patterns just floating by in prisms in front of me, in a way that makes it seem as though light is bending and separating. this then turns into numbness that starts in a wave from my head out to my extremities, moving from a palsy-type attack with the droopy mouth into something that feels more like a stroke. and, when that wave has passed through me, i'm left with a throbbing headache - and extreme tiredness - that can last up to 48 hours and usually requires a day or two worth of sleeping to shake off. it tends not to go away until i go for a walk or a bike ride - just go out and get some fresh air.
it seems to be triggered by dry air, car exhaust, second-hand smoke & general pollution.
tonight seems a little better, but i know better - i'll be knocked out as soon as i'm done trying to move the air out and cleaning up the consequence, and i'll no doubt be asleep until tuesday.
ugh.