Hcg levels

So when I first went to the doc they put me at about 6 weeks because of my lmp, but when I went for my ultrasound the lady told me I was 6 weeks with a healthy baby so far and I should have been 8 almost 9 weeks at that point. However, at my initial appointment my hcg levels were 24,140. I've read that this is way high for someone who would have been 4 weeks if that. What do you ladies think. Oh and I also feel like my ultrasound tech didn't do such a good job.