Help! Electrolyte imbalance or anxiety?

Hello! I'm an F, 23, 130 lb. Iget frequently anxious about health issues and I've been to the ER many times, thinking I may be having anything from a heart attack to septicemia, candidemia etc. after reading about the symptoms. About a month ago I had the flu for a week, with fever, diarrhea, low appetite. The symptoms subsided, but I was left feeling a bit weak and lightheaded after, which made me think I have an electrolyte imbalance. I took fluconazole(2 150 mg doses) for a candida infection right after the flu, and I read those can cause changes in potassium levels. I've been having what I think are heart palpitations, my resting pulse varies from 59 to 75 or so at different times, sometimes I feel my heart pounding, sometimes I feel it's too "weak". I get lightheaded sometimes, usually after walking a lot, and when I panic. I've been trying to eat potassium rich foods, though I can't reach the recommended 4700mg. I'm scared I may have an imbalance that could cause cardiac arrest!