I am experiencing right side headache, pressure behind right eye and lightheadedness. the following also describe me: nasal congestion and fatigue. what should i do?

See a doc: Right sided headache and pressure behind the right eye in the company of nasal congestion points to the likely presence of sinus disease. If you are using antihistamines to get relief, your fatigue may be a side effect of this. Lightheadedness may come as a result of fluid depletion from the sweating of fever, and not drinking enough to replace your losses. See a doctor for more personalized care.