Sudden Fever, Rashes, and Abdominal Pain

I have been experiencing sudden fever and severe chills (ague) while sleeping at night. The fever started abruptly on the first night, accompanied by intense shivering, cold sweats, and body aches. On the second day, red, itchy rashes appeared on my body, which visually resemble pox. By the third day, I started feeling a sharp, flash-like pain on the left side of my abdomen. The fever fluctuates, and sweating occurs as it subsides. These symptoms are concerning, and I would appreciate your guidance on possible causes, necessary tests, and treatment options. I am also taking fibator 10 for cholesterol and udiliv and evion for grade 1 fatty liver and Amlodac 2.5 for controlling blood pressure and an antacid daily.