A 32-year-old primigravida at 34 weeks gestation presents to the emergency department with sudden onset of severe abdominal pain and vaginal bleeding. On examination, she is restless, blood pressure 100/65 mmHg, heart rate 112/min, and the uterus is tender and rigid. Speculum examination shows active vaginal bleeding. Ultrasound reveals a retroplacental clot measuring 4 cm × 3 cm with fetal heart rate 145/min. Hemoglobin is 9.2 g/dL (baseline 11.8 g/dL). What is the most appropriate immediate management?