Went in for part 2 of my heart test. Did not go as planned. :^(
Not entirely sure what happened, but the first go at putting in the IV didn't work. It was a bit painful and that got me a little woozy. I fought it for a while but then lost the battle. Woke up later with the nurses around me setting up an EKG, testing my blood sugar, and putting me on oxygen. Also had a lovely cool cloth on my forehead.
They told me I went very pale and passed out. My bp was something like 100/60 something and my pulse was in the low 60s. These weren't horrible numbers, which prompted them to try and find another reason why I conked out. Blood sugar was fine, as I expected since I am not diabetic. The only thing I can think is that it was the combo of me having taken my blood pressure med today when I was probably already near normal, and the pain of the needle, which reminded me of a very bad experience I had as a child with an I.V.
Beyond that, the actual testing portion of the day went fine. Here's hoping for good results. 
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Needles are bad enough. When they stick you and THEN start looking for a vein is worse. But passing out because of a bad childhood experience is the worst. So sorry. 
I think we've all had bad needle experiences. I remember one (kindergarten) that involved seven doctors, a lead X-ray blanket, a table, a nurse to administer the procedure, and probably a healthy supply of ear plugs.
After what I've been through in the last few years, I don't even wince at needles now. In fact, I have to give myself an injection every day. But I can relate to the bad I.V. - one made my arm bruise up (swlollen even) for three weeks. My GP said that happens sometimes and as to his word, a few weeks later the bruise was gone. But damn was that bothersome.
Keep us posted on the results!
It's a vasovagal reaction, an autonomic nervous system response from watching or experience a medical procedure (in your case, venipuncture). Has nothing to do with bp or illness. "All in your head" so to speak. 
Since you said it reminded you of a bad experience as a child, that's probably the trigger. Next time, have then draw your blood while lying down after resting for a few minutes. Keep your eyes closed and don't look at the needle.
I'll keep my fingers crossed for good results!
