I Have Been Having Palpitations For The Past Five Days.

I've been having palpitations for the past five days. I had to visit the ER last month and they found my potassium slightly low. They performed all kinds of tests and gave me potassium to drink. I felt better and they sent me home after two days. Now it happened again so I went to the ER and they found everything normal. My potassium was at 3.9 and everything else was ok. Symptoms are worst when I rest on the left side of my body or flat on the bed. I will see my cardiologist this week as recommended by the hospital. I had a holter about 8 months ago for 24 hours...should I ask my doctor for the 1 month one? Do I need not to worry about these symptoms since everything looks normal or keep searching for the cause of these palpitations? Thank you!