I would think eyesight problems might do that. My lens in my glasses had twisted because the screw was loose, and it took three trips to the eyepeople to find one who saw that. It felt like my eyes were going crazy! My problem is falling asleep!!! I'm knitting the One Row Scarf from Yarn Harlot's site, and it's very relaxing. I knit and knit and fall asleep.
Hope you figure it out soon! Knitting shouldn't make you sick!