I would tend to disagree. If you last period was November 2, then at 4 weeks of pregnancy that would be around December 2. Then 8 weeks of pregnancy would be around January 2. To get closer to today, add about another week of pregnancy, so you are around 9ish weeks of pregnancy - not quite 11 weeks. My early ultrasound said that I was about a week and a half off of when I knew I ovulated (test strips). Some of us ovulate later, and some of us even implant later (that's me!).
So at this point I wouldn't give up hope at all. I think you calculated your dates a bit off, if you are a later ovulater, a late implanter and maybe baby is a slow grower then all these things can add up to a week or so difference. And maybe the ultrasound showed 7 weeks and a few days - there is some more time!
I would take it easy and do as the dr says, but don't give up hope yet. I wouldn't determine threatened miscarriage until some hcg numbers start showing weird stuff!
it sounds like threatened miscarriage unless your dates and ovulation are off. reast over the next week and good luck