Aiyoyo, first baby kan memang kena worry about everything! The glucose bubble (yolk sac) mmg should be visible early on around 5-6 weeks, tapi kalau doctor say baby growth is normal and good, that's the main thing lah, means baby is developing properly. Sebab tu I'd suggest confirm with your doctor on the next scan or appointment, sometimes it's just the angle or timing of the scan, atau maybe your dating is slightly different from what the scan shows, so jangan stress dulu okay. A few of my mum friends juga had similar "missing" markers on early scans but everything turned out fine, so try not to overthink.