Hello

last night when I went to bed an uncomfortable high pressure feeling developed quickly in the top of my head as soon as I lay down. If I sat up it disappeared. It stopped my sleeping for a couple of hours and I opened the window and tried to have as much fresh air as possible. 

I have not experienced this before but had been painting for 3 hours using turpentine substitute with one window open. I often paint for 2-5 hours and have never had this experience before, I don't always have a window open.

Is it possible this was not enough ventilation and if so what amount is needed? I was also using bigger jars than usual to mix my brushes.

Thank you for any advice.