rebalancing

Yesterday I learned that rebalancing wheels is not what I thought it was. I assumed the car would need to be there so the wheels either side would get balanced. But apparently it's more to do with the flatness of the tyre ( or something.)

I personally feel a bit more balanced now (it wasn't even my tyre that was being rebalanced). Tho I have a meeting this morning in a building I have frequented twice recently and both times emerged with a massive headache despite drinking water. I know that I don't do well if I'm in a room with no window, the electric lighting and lack of air get me every time. Which is curious as by night I sit in a room with electric light and the curtains drawn and I don't get a headache then, I wonder why? Anyone any top tips on how to survive those kind of rooms/meeting, please do share :)

(Yay, today it was in a room with a window!)