Heart palpitations

About a month ago was when I started having heart palpitations and I had them for about four days and then they went away and last week it started again this time I can really only feel them when I’m laying in bed or relaxing. I’m seeing my pcp on Friday for it and I can only think it could be because of low potassium or low iron. I googled it and other major heart problems are accompanied by chest pain, difficulty breathing and dizziness which I don’t think I have unless I get up too quick. I already have anxiety but like these heart palpitations aren’t anxiety related because I feel dumb even when I’m not anxious. I’m like really scared like what if it’s something that’s actually like a major health condition. Is my dr. going to suggest a blood test to see if I have low iron or low potassium I feel like that could be what’s causing it I hope that’s what causing it that way it’s not too dangerous I could be easily fixed