you could try cutting down your potassium to 100mg a day for a week and see if your headaches go away?

i just got my labs back, and it looks like my potassium is within range but close to being too high. and, i'm only taking 100mg of potassium a day. it is not good to get too much potassium, don't know for sure if it would cause headaches though. you could get a metabolic panel done and see where your potassium is.