Horrible headaches are part of what 2-butoxyethanol does.
Why? I suspect it is the immune system attacking you - maybe at the pituitary ... or it could be anywhere in the brain ... immune system attacks you in lots of ways, sometimes with arthritis, etc.

It seems to cause diabetes, primarily, so I thought there had to be something autoimmune about that. And there is

So ask your doctor how to stop your immune system from being autoimmune. I think they offer immune suppression, or medications 'to help you cope' I think these harm you, as you are dealing with a chemical exposure & more chemicals, regarless of the type, add to your chemical load ... "No! No!"

I noticed poor Lorenzo was given a bout of immune suppression. Leukodystrophies have an autoimmune aspect, as does Autism This is Autism Awareness month , by the way

Products? Here are a few ... add to that Simple Green, oven cleaners, gun cleaners, probably jet fuel, too! No wonder the sperm is declining among our men these past 4-5 decades

Check the products you use. Or, when do you have 'flu-like' symptoms? What were you doing then?