Sometimes you can pinpoint part of the harm if you can remember what you were doing then? There is a chemical that causes eyes to burn like pokers; then flu like symptoms, and dark urine and fatigue big time. It is 2-butoxyethanol and it is in lots of products; it is not safe to use. It causes all the symptoms you've mentioned, but of course there are more. Please look it up on the internet & read up on it. (Basically same symptoms as 'gulf war syndrome' Are the headaches searing ... not the normal type of headache? (This chemical is a solvent, a pesticide and a poison; it causes endocrine disruption and targets liver and kidneys, Central nervous system and blood damage first and foremost.)