Does repeatedly adjusting the needle causes the blood flow to diminish ?

From experience my blood flow is always slow at the beginning and then it gets to a normal pace. During my last donation, the nurse kept adjusting the needle to find a way to increase my flow. I told it was hurting me and that normally my flow increases by its own. She kept the needle in her hand for a couple of minutes and I could feel all the little movements. At one point I was told my blood flow was zero and they stopped the donation, I'm kind of frustrated... Is there a link between a slow blood flow and moving the needle ?