Replying to Donating blood

i donated blood for the first time today, primarily just to see what it was like. after it took about 10 minutes to fill the bag i felt ok...until i watched the nurse put the needle in one of my professors and saw the blood shoot into the tube. it didn't freak me out at all, but all of a sudden i felt ridiculously hot and starting sweating bullets and hyperventilating. after 5 minutes like this and almost barfing i felt a little better.

also, getting the needle put it EFFING HURT!

anyone else donate blood? i don't think i'll be doing it again.