A 4-year-old child presented with decreased urine output for last 20 hours & petechial spots over the body. There was a history of diarrhea 2 weeks prior to this. Blood investigations revealed a Hb level of 7 g/dl, TLC 11,800/mm3, Platelet count of 35,000/mm3. His peripheral smear findings are shown belowWhat is the diagnosis?