Aiyah, 0.5kg in a month is really slow lah mama! At 13 weeks, you should ideally be gaining around 0.5kg per week, so the nurse betul jugak to nudge you. Honestly, I'd ask your doctor to check your thyroid and make sure baby's growing properly on the scan, sebab sometimes ada underlying issues yang kita tak realize. In the meantime, kena makan lebih sering, try snacking between meals (nuts, fruits, yogurt), drink more milk or Milo, and make sure you're having enough protein at each meal; a few of my mum friends struggled with weight gain and adding protein powder to their drinks really helped. Jangan worry too much okay, but do take it seriously because baby needs the nutrition, maybe the doctor can refer you to a dietitian if needed.