A nurse is caring for a client who presented with nausea and extreme fatigue. Nurse's Notes: 0915- Client reports worsening nausea and fatigue, stating he feels lightheaded when standing. Skin turgor is poor and mucous membranes appear dry. Client denies any recent infections or changes in medication. 1130- The client appears increasingly lethargic and has difficulty maintaining focus. He has not eaten or drank anything in the past 12 hours. The client has an indwelling catheter which has drained 200 mL over the last 12 hours. Glucose level is 81 mg/dL. Vital Signs at 0900: Temperature 36.8 C (98.2 F), Heart Rate 110/min, Respiratory Rate 21/min, Blood Pressure 90/60 mmHg, Oxygen Saturation 98 Vital Signs at 1200: Temperature 37.0 C (98.6 F), Heart Rate 115/min, Respiratory Rate 22/min, Blood Pressure 88/58 mmHg, Oxygen Saturation 98 Which condition is the client most likely experiencing?