Alamak, I understand why you're worried lah! Honestly, every pregnancy is SO different, some of us have crazy morning sickness, some don't have any at all, and that's completely normal. A few of my mum friends had barely any symptoms at 7 weeks and everything turned out fine, so the lack of alahan doesn't mean anything is wrong. That said, since your doctor already noticed no heartbeat at 5 weeks and asked you to come back at 9 weeks, I think the best thing is to just follow that appointment, the waiting is nerve-wracking I know, but that scan will give you proper answers. In the meantime try to stay calm (easier said than done!) and if anything changes or you get worried, just call your clinic, no harm asking them to reassure you or move the date earlier if you really can't wait.