Thank you for posting your question here, I will try to answer it to the best of my abilities.
Have you had a blood test
done, to check for infections and besides potassium is any other electrolyte in the lower levels? If you havent had these things checked, I recommend you get them checked and then post the results here or ask your doctor to explain the results to you. Hopefully we can find what is wrong with you from these simple tests.
I hope this helped.