Cough, Vomit And Fever. Why Do Calf Muscles Hurt? Is It Ebsteins Anomaly?

My seven year old daughter has been sick for 4 days now, it started with vomiting and high fever , and in the last two days she is coughing and still has fever that goes up to 38.5 C , we did see a doctor yesterday and he said that she looks ok at the moment and just to monitor her and see if she gets worse to see him again, but this morning she woke up with 38.5 fever again and her calf muscles hurt so she finds it hard to walk, she walks, but does it slowly and carefully. I asked if any other muscles are aching and she said no. She does have Ebsteins anomaly and it just makes me worry a bit more in case it is something more serious like reumatic fever. i