HI, I'm 9 Weeks Pregnant, I Had A US On

HI, I'm 9 weeks pregnant, I had a US on 7th week & saw the baby with heartbeat showing 6 weeks & 2 days. I had a little small light brown discarrge also not all days only sometimes. MY DR prescribed me primoult 250mg to take once in a week 4 times. I had 3 injection and when I went for the US on 9 the week the baby is showing the same status with no heart beat. I dont have any stomach pain. She tols me to take a beta hcg blood test. for the first test it shows 12,582, second i have to do on saturdAY. She is telling me it may be dropping. What is actually happening