HCG results

So according to the first day of my last period I should be 5-6 weeks. But I just got my first blood draw HCG results today and my level is 12,451.....is it normal to have such a high level at 5-6 weeks? Could I be farther along than I thought it could I be having twins?? Help. My Obgyn said they won’t see me until I’m 8 weeks according to the first day of my last period which isn’t until 2/3 and that is stressing me out. I need to see that my levels are increasing and I want to see my little peanut in a sonogram. This is my first pregnancy. I also want mg HCG level explained to me by the doctor. Can anyone give me any insight to my levels ?