I've never gotten one from smoking... I have, however, from stress.

Everything got extremely fuzzy... not like visual, just my thoughts, like this bad buzzing...

I started breathing so hard and fast, I felt like I couldn't breathe. My head started going numb and I could feel the muscles on my face falling asleep...

I fell to the floor trying to catch my breath for half an hour before it finally went away... I don't quite remember it, but it was highly unpleasant.