Stress Overload = strange headache

This weekend I got a very bizarre headache, that has not entirely gone away (it comes and goes, with little corrolation to much of anything). The only cause I can think of that makes any sense is stress overload. Now, why is the headache 'bizarre' and why can stress be the only cause? The headache is bizarre because, for the most part, it is not painful. It is like feeling light-headed and wozy, but, instead of the room spinning, my vision going black, or lossing my hearing, is feels like different parts of my brain are on a variety of little boats on a stormy sea. Yes, it feels like my brain is beginning to feel seasick. Such an unusual headache is generally generated entirely by one's imagination and little else could be the cause, besides stress overload.

My bizarre headache prompted my to think about the mechanisms that probably over-react to cause a negative physical reaction to stress. Are they evolutionarily sound when not exaggerated? Were they once usful, and now remain only because humans have learned how to cope? Or was the negative physical reaction to stress selected itself?

I thought about all that yesterday, but today I was reminded, looking through my readings, that a similar question can be posed about autism? Was autism itself selected for? Were less eccentric versions selected for and autism is the unfortunate extreme? This, in turn, relates to society's view of autism and its 'usefulness'. There appears to be a debate now over whether or not to try to rid the world of autism, to remove the autism gene(s), if it becomes possible. The very fact that there even is a debate shows a shift in attitude towards autism. Before, it was nothing but a horrid disease; now, it could be something highly useful to keep in the gene pool.