I was totally hoping it was 30 tests and less vials. But, hang in there, you will get through!
Hang in there and good luck!
PS-But, just to make you feel better, bring someone to drive or take a cab. You don't want to feel pressured to drive if you are feeling icky after. Personally, I was under weight to give blood (by about 5 pounds for my height) but never had a problem when they did big draws. Finger's crossed it's the same for you!