What to do if I have had blood test done for a physical, and my potassium levels are very high. Any help?

Get it rechecked. It is probably a lab error. It is not uncommon to have this false alarm because potassium level does not go up if you are well. It usually goes up if your kidney is not functioning. Most of the false alarms are caused by a difficult blood draw which can dmage the red cells which relase potassium into the blood. But it is nothing to worry about..You just need to confirm it.