My 6 year old son has had a fever for 8 days that develops at the same time each day ( around 3pm). He has also been vomiting many of those days in the evening. We have been to the pediatrician twice. He tells us to keep him hydrated and has prescribed amoxicillin which my son has taken for almost 4 days. We are keeping him hydrated with Gatorade and pedialyte. He seems fine during the day except for a wet, constant cough and feeling weak. But once 3pm comes, he is extremely tired and spikes a fever. Do you have any idea what my son might have or what we can do to help him?