Your symptoms of fever, body pain, tiredness, nasal congestion, and throat pain are most commonly due to a viral infection such as flu, where antibiotics like Mahacef 200 (cefixime) are usually not needed unless a doctor has confirmed a bacterial infection. Diclogesic can reduce pain and fever temporarily, but it should not be used repeatedly without medical guidance. The most appropriate approach at this stage is rest, drinking plenty of fluids, steam inhalation for nasal blockage, warm saltwater gargles for throat pain, and taking a painkiller when needed. Most viral infections improve within a few days, but if fever persists beyond 3-4 days, becomes very high, or you develop breathing difficulty, severe weakness, or worsening throat symptoms, you should consult a doctor for further evaluation and tests if required.