Hi, Just Wondering What The Risk Of Getting HIV From

Hi, Just wondering what the risk of getting HIV from an infected needle during a blood test are. I recently got a routine blood test done ... when I entered the room, the needle use to draw my blood was already attached to the apparatus and i am unsure if if was a new needle. A few days after the test, I developed severe flu, sore throat and was worried that the needle might not have been changed. I could not see any visible blood on the needle and my understanding is that even if the blood was microscopic, exposure to the air means that the HIV virus should have died. Would appreciate your opinion as i am quite worried.