Hi. Thanks for your query. Noted your history of passing blood in the stool and started with fever and very bad headache after a few hours. If all the three things have started together, the most probable diagnosis is obviously intestinal infection leasing to blood in stool, the toxemia causing the fever and the headache. I would advise you the following in such a situation: Rush to the ER or the nearby hospital. You may need urgent admission for clinical evaluation, examination and investigations for proper treatment. Get the stool examination and urinalysis. Send blood for CBC, culture and sensitivity and liver and kidney functions. You need intravenous antibiotics and fluids and further treatment as per the clinical evaluation and investigations reports.