HI. My Son Is 8 Years Old. For The Past

HI. My son is 8 years old. For the past week, he has had nightly fevers ranging from 99 - 102 degrees. He is FINE in the morning and all day; active, goes to school, can concentrate, etc. The fevers come right around dinner time. He then feels extremely fatigued, looks pale and ends up not eating dinner but going to sleep instead. He also has a rather persistent, dry cough. We saw the Dr. on Friday and they said it was just a virus but it hasn't gone away. Help.