Aww mama, nausea and vomiting boleh lagi happen even at 24 weeks, especially lepas makan tertentu, few of my mum friends experienced the same, sebab perut dah tight dengan baby growing. Try makan smaller portions, avoid fatty or spicy food, and sip water slowly throughout the day rather than gulping. That said, if it's happening every time you eat or you're losing weight, better check with your gynae just to be safe, sometimes ada reasons yang need attention, and you want baby to grow well kan? Hang in there, mama!