I don't find digi's very accurate Sunshine. With DD I got a 3+ before I was 5 weeks, turns out that was because my HCG levels were extremely high!
With my mc I got 1-2 for ages and then 2-3 the day before I mc.
This time I got a 2-3 when I found out (5 weeks) and 3+ this Monday just gone at 7 weeks, maybe I would have got the 3+ earlier but I wanted to be sure so waited a while.
Don't forget they use an average HCG on the conception indicator, even though the numbers aren't going up as you expect the pregnancy is still progressing well. Is there a chance you ov'd late?