Funny thing, I was petrified of needles until I trained as a military medic and learned how to take blood, give injections and set up IVs, which we practiced on each other. After gaining operational experience I found out that I no longer feared needles myself.
I'm not suggesting that you should join the army to cure your phobia but obviously by confronting the fear it removed it. Why not talk to your GP who may be able to arrange for you to watch a flu jab session at your local GP practice or spend a couple of hours with the phlebotomists at your local hospital. Possibly not but it can't hurt to ask and you never know, once you've seen a load of other people being 'needled' it might just displace your own fears.
I'd be interested to hear AME&PPL's or any phobia experts' views on this.
BTW, my ex was and still is absolutely terrified of needles, so much so that she fainted at the propsect of having a local anaesthetic prior to having a wound sutured. They brought her around and she fainted again when they went to inject her so the second time they just left her unconscious and sutured the wound quickly while she was out. She will not have any anaesthetic for dental work - hard as nails....or bl**dy stupid!!