I have donated dozens of times. In the military we would give a pint and drink a pint. Stupid thing to do but you do catch a good buzzz...
Your getting sick was probably a coincidence. Worst experience I had was on one of the mobile units that cruise Houston. Damn nurse missed my vein and hit something that shot a pain through my entire body. Then she pulls the needle out and resticks me. Last time on one of those buses.