A 32-year-old female presents with 4 days of myalgia and fever after overexertion during rice harvesting, accompanied by cough, abdominal pain, and one episode of hemoptysis (50-60ml). Physical exam: temperature 39.2°C, pallor, conjunctival congestion, heart rate 140/min with gallop rhythm, bilateral lung rales/crackles, and gastrocnemius tenderness. Presumptive diagnosis of leptospirosis is confirmed by lab tests. The primary treatment is: