5 year old child presents with reduces urine output since 1 day and petechial spots all over the body, there was history of diarrhea 2 weeks brier to this. Blood investigation showed Hb - 7gm / dl, TLC - 11,000 / MM3. PLATELET COUNT - 20.000/ mm3, peripheral smear of this child is given below. what is the most probable diagnosis?