Its from the nicoteen as others have said already...

when I first started smoking I smoked a really full bodied smoke on an almost completely empty stomach...

bout 1/3 of the way thru I started getting a little light headed and dizzy, but I kept with it cuz it was a good cigar

then about 2/3 of the way thru I was really really dizzy and was in a cold sweat... but still it was a good cigar

finally when I finished it off I was way dizzy in a cold sweat, shaking and feeling naucious

was a good cigar... but I sure learned my lesson about eating before smoking a cigar I'm not familiar with....