How to deal with a blood test with an EXTREME fear of needles?

I might have to get a blood test done, and I am deathly afraid of it. Like, I just had a complete breakdown, and cried nonstop for a good 30 minutes when my dad told me I might have to get one done. Just the THOUGHT of it gives me an extreme anxiety attack, to the point where I feel like I'm about to either throw up, pass out, or both. I freak out just getting a vaccine. I can't control it, and it's embarrassing and scary, and I don't know what to do. Please don't tell me that I need to just grow up, or anything like that because if I could control myself, trust me I would.