Confused 🤷🏻‍♀️

I'm 6 weeks & 2 days today . Yesterday nurse practitioner called and told me that my HCG levels increased 2,770 over the passed 5 days . Which 5 times the previous number . Nurse still wants me to go to an sonogram done at another facility to see if we can see a sac because she feel as though my levels should be EVEN higher . Which scares me . I always thought as long as the numbers doubles or more your fine which mines defiantly did . So I'm confused should I be worried .? And since I'm going to another place this won't be done transvaginal right .? So will anything be even be seen doing it on my belly .?