Headache, nausea and fatigue

Migraine may cause head pain, nausea, light sensitivity, and a drained feeling before or after the pain. Viral illness may add fever, sore throat, cough, or body aches; this can occur with a Common Cold or COVID-19. Low fluid intake, vomiting, heat, or diarrhoea can lead to Dehydration. Nasal blockage and facial pressure may suggest Allergic Rhinitis or Chronic Sinusitis. Anxiety and disrupted sleep can amplify pain and reduce energy.

Rest somewhere cool and quiet, take small frequent sips of fluid, and eat light food when tolerated. Note the onset, temperature, fluid intake, sleep, medicines, and any exposure to illness. Follow label directions for any pain relief and avoid combining products with the same ingredient. Contact a clinician if symptoms persist, keep returning, or prevent normal activities, because an examination may be needed.

Seek emergency care for a sudden severe headache, new weakness or numbness, confusion, fainting, seizure, trouble speaking, vision loss, severe neck stiffness, or inability to keep fluids down. Get prompt advice for high fever, a new rash, worsening drowsiness, or symptoms after significant heat exposure. Dengue Fever is relevant after mosquito exposure with fever and marked body aches.

Could this be migraine, infection, dehydration, or a medicine effect? What should I monitor at home? Which symptom would change the urgency?