In aftica. could i have dengue fever?

Maybe: Dengue fever is endemic in parts of africa. It depends where you are and the conditions there. If you suspect dengue, see a doctor.

High Fever: According to the cdc suspect dengue if in an endemic area & you have high fever (i.e. 104 f) which presents with two of the following symptoms: muscle & joint pain, severe headches, intense pain behind the eyes, nausea, vomiting, swollen glands & rash. Severe dengue can lead to drop in body temperature, bloody gums or vomitus, severe abdominal pain, difficulty breathing & restlessness. Take care.

Foreign Travel: Depending on where you traveling you can be exposed to various diseases. Malaria would be my first concern. Would see a doctor as soon as posible.