I want to know the reasons for reduction of sodium chloride and potassium in the blood. What are the signs and symptoms of such reduction? What damage does it do to the body? How to maintain the optimum level of the two contents?

I recently went to the doctor because I was having difficulty breathing, rapid heart rate when at rest and a tight (heavy) chest.
The doc says it sounds like anxiety, however she took my blood to test for a thyroid condition (runs in family) and I have a heart ultrasound scheduled for tomorrow.
A bit ago the office called and said they want to retest my blood because it came back showing high levels of potassium. How common is a false positive (hoping its false) and what does this mean?
FYI- I am a 23 yr old female, average weight, and a smoker

the list should be like
apple 1 medium 140mg
banana ….
……

***** SUPER IMPORTANT PLEASE READ******* I was trying a tre flip lip for about a half hour. It was like 90 degrees and almost 90% humidity. I had already drank a full water bottle and two gatorades. The town shut off the water fountain and someone broke it, so the town refuses to fix it and turn the water back on. Anyway, by this last fall, I had lost all energy, as you can see by me trying to get up and just falling back down. The part’s you don’t see (which are actually more important) is …

what causes low in potassium and sodium ? what are the food need to eat to recover ? how long ? does urine many times cause low in potassium or sodium ? pls help ?

or if you know of a better one let me know