Writing to confirm. My own experience was very similar but the extreme disorientation lasted only about two minutes with minor disorientation for another five or so. Not recommended.
19 yr old, male, Maths&Physics student from UK. Lurked on OB, then started lurking here when this place was made.
EDIT: In case you want data on abnormalities among lesswrong lurkers here's two: Raised in Colombia as the son of missionaries. Self-taught.
Writing to confirm. My own experience was very similar but the extreme disorientation lasted only about two minutes with minor disorientation for another five or so. Not recommended.