Blood levels

Kami

So I just found out Monday Jan 14 that I’m pregnant. I went yesterday to the dr to get a confirmation and blood work done before I schedule with an obgyn. The dr just called me to tell me that my bloodwork came back to 15 weeks. According to my last period, I’m supposed to be 6 weeks. I know it’s possible to have periods while pregnant, but is it also possible for it to be more than one baby?