You may be experiencing a viral infection such as a common cold or flu. Make sure to rest, drink plenty of fluids, and take paracetamol to help with fever and headaches. Gargling with warm salt water, using an antiseptic mouthwash, or taking lozenges can soothe your throat. A saline nasal spray or steam inhalation may help clear your nose. If your symptoms worsen, last more than a few days, or you have difficulty breathing, please consult a doctor promptly.