Has anyone ever been through this?

Le
I went into my dr day before yesterday. I am 7 weeks. They did a vaginal ultrasound and couldn't find anything. They tested my hcg levels two weeks ago they were 831. My dr sat me down and basically told me that if nothing was seen on ultrasound at 7 weeks that I'd miscarried and checked my hcg that day just to confirm. I just got a call from her that not only had my hcg gone up that they were extremely high, and she wants me to come back in Monday to check if it's a molar pregnancy. Question, if it's a molar pregnancy wouldn't she have seen something on the ultrasound? There was nothing. It just looked empty, and that's exactly how I feel! Does anyone have any advice or have been through the same thing?