I have to use oil paint to redo someone's bathroom tomorrow, I would probably get very high in that enclosed space if not for using a mask. The high from confined oil paints sucks. You can taste the paint in your bloodstream, in your mouth and on your breath for hours after you are done painting.

EDIT:
You probably are not using enough paint to get high from it. I am not sure, maybe you should clean your brushes in a huge bowl full of solvent and keep it right next to you?

Also, no offense if you know this already, but you can cut oil paints with solvent and then paint with them if you want a thinner look to the paint. It seems obvious but for some folks it isn't.

What solvents are you using? I like Varsol (which is Canadian for paint thinner) but sometimes Acetone works better.