I always drink lots of water before any blood draw. I have no trouble with them finding the vein or taking blood or the pain, there are different types of needle phobia. I get a Vaso Vagal response where my blood pressure and pulse rises before the test and rapidly falls once the needle is inserted. If I wasn't sitting or lying down, I would have passed out. My fear of needles is the "Fear of a sharp object puncturing a vein or artery". As for Gitelman syndrome, yes I take 3 x 600mg Potassium Chloride tablets twice a day, 2 x 500mg Magnesium Aspartate Dihydrate twice a day and a Potassium Sparing Diuretic twice a day - (I used to use Amiloride Hydrochloride, but it is no longer available where I live and now I have to use Spironolactone, which works, but has some side effects) My Potassium and Magnesium levels are now normal - but took several years and lots of blood tests and adjustments to my medication to achieve this.