Yeah, this was at a historical site on many acres, with many old buildings, and no specific signage. I parked, walked and walked, went back to the car, drove, parked again, and walked and walked some more. Found the correct building, walked all through it, finally found the blood drive. (To be fair, though, the previous time my temp was too high, it was at a completely different location and didn't involve much walking.)
I'm also very, very anxious about the whole donating process. I have wondered if the anxiety might also raise my temp.