Fever for 35 days & cough

Patient: Hi there, I have had a fever since monday at noon (3.5 days to date) and today it is accompanied by a cough. This morning the fever didn’t come and I though the worse was over, but in the evening my fever returned to 38.5 degree. The cause of the fever is unknown…Can you help me?

Symptoms: Coughing, relapsing fever, chills, headache (not sure if from caffeine withdrawal or from fever)