Bud i know where your coming from!! i pass out when i have blood tests.

first time i did it wasn't even me having the blood test!!
went to meet my new niece, she was in the special care unit and whilst i was there they stuck a needle in her foot to take some blood, i some how managed to turn away and pass out and up head first into the wall missing 6 incubators!!

then 3 months ago i went out cold in the middle of specsavers!!
had gone in for a first fitting on contacts, had them in a few minutes and like you i started going cold and sweating etc..... as they took them out i went out like a light!!
i remember coming round to some one shouting "medic" and then for the next 30mins i had all the little dolly birds checking on me!!