A pregnant woman - fever and a bleeding tendency - next steps?

Gravida 1,31 weeks, 26 years, complaints of epigastric pain, bleeding per gum and petechiae hemorrhage for 1 day; high-grade fever for 5 days prior to admission, first seen at antenatal clinic (12 weeks pregnancy), no abnormality detected. Nothing history. 37°c, bp110/80 mmHg, pulse 80/mim and respiratory rate 20/min. Mild dehydration. Liver enlarged 1 cm below the right costal margin with mild tenderness. Fundal height - 31 weeks' gestation, fetal heart rate 144 beats/min, Petechiae1–2 mm d. found on face, forearms and both pretibial areas.

Labs: hgb 11.9 g/dl, hematocrit 35%, white blood cells 7,440/mm3 50% neutrophil, 45% lymphocytes; 3% atypical lymphocytes; platelet 10,100 /mm3. Intravenous fluid replacement, under close observation bleeding precaution. After 24h, epigastric pain disappeared, vital signs normal. Hematocrit 30% , platelet  6,320 /mm3. Day 3, gradually recovered and had an itching convalescent rash on both pretibial areas. Hematocrit 31%, platelet 15,000 /mm3. She was discharged day 4. After 1 week, she was healthy and hematocrit 32% with platelet 354,000 /mm3. After that, she had an uneventful antenatal care. At the 39 weeks' gestation, she delivered a healthy female baby weighing 2,630 grams by vaginal route with APGAR scores 9 and 10 at 1 and 5 minutes, respectively. No abnormality in newborn was detected.

Most likely diagnosis of this condition?