You were prob. low on potassium even on the IGD because while milk does have some potassium, it's nowhere near the amount in a potato, banana, avocado, coco water. Everyone is a little different with potassium, some people can seemingly stand not getting much while others can't tolerate even the slightest reduction.

Strawberries are good sources of potassium too so keep it up with the smoothies - toss a nana in there too!