It can be any number of things, sometimes doctors need to give symptoms time to develop to assist with the diagnosis. A virus at 5 days might look the same as a fungus at 5 days. After 30 days the symptoms of the two conditions might be different, giving a clearer idea what it is and pointing the doctor to a new line of investigation or treatment. Again its only able to be diagnosed by a doctor, and none of us here are doctors. There is nothing to be gained by Googling symptoms, leave it to the doctors.