Well, it started well. My blood donation this evening featured my highest iron level in quite some time - a good bounce back from the low of the previous donation. After the donation though, I rested for ten minutes and then got up and went to the toilet. I had drunk a lot before the donation. However, while I stood letting nature take its course I felt a little lightheaded, and as time went on my eyes were fuzzing over. I managed to finish and zip up before lurching out of the room and then staggered straight for a couch, while at the same time muttering something to the nurse in the kitchen area. She knew what to do - and then enforced the procedure to the nth degree. I had to stay flat on my back, feet up high with ankles and wrists rotating and coughing till she said (this was to get the blood flowing back to the brain). Then I could put my legs down. And then five minutes later I got a pillow under my head. And then 5 minutes later she let me sit up. And then I had to stay for about 20 more minutes. But on the positive side, they paid for my taxi back home! I actually got back right when I said I would.
This is the first time in 23 donations that I've had an adverse reaction. But it is a good lesson in what to be careful of as well as the procedure for when someone becomes lightheaded.