I'm seeing spots

When I sit for too long knitting away, and then have to get up I get this huge head rush. For a brief moment I see spots swirling around me.

Giant slippers? No, Fiber Trends' felted clogs (pre-felting). This was a blast to knit up. I recently learned that wool socks and carpet are not a good combination. The polyester in the carpet pulls on the wool fibers and will cause thinning in places like the heel. This makes sense because this has happened to a pair of socks I knitted last fall, the heel is worn and thinning, hanging by a thread. Wonder if it will do the same to felted wool. May take longer to wear out since the fibers are so tightly bound.