Alhamdulillah baby's weight looks good at 29+ weeks, 1.5kg is actually on track lah, so jangan risau sangat about the app estimate, those calculators boleh berbeza depending on measurement. The fact that baby's head dah turun and doc says ada space lagi for turning is a good sign, so InsyaAllah everything moving along nicely! About your weight drop, common je masa pregnant, especially kalau morning sickness or just the way your body is distributing things, tapi since you're eating well, best to mention it again to your doc at the next check-up just to be safe lah, in case ada anything minor they want to keep an eye on.