Aww sabar ye, I know how stressful this is! Since you've already been to the dietitian and she's eating regularly, definitely follow up with your pediatrician again, sometimes it's absorption issues or something else yang kena investigate properly, especially if the dietitian can't pinpoint it. A few of my mum friends had similar worries and it turned out their little ones just needed tweaks like higher calorie snacks (peanut butter, avocado, eggs), or the doctor found something kecil je that made a big difference once treated. Hang in there, mum, you're doing the right thing by seeking help!