Miscarriage hcg levels

My doctor called and said my hcg levels have dropped from 310 to 260 something atleast it's not that big of a drop. She didn't say I had miscarried I guess she doesn't wanna say it yet...anyways she says she wants to do an ultrasound and heartbeat and blood test 2 weeks from now why is that?? And I'm not bleeding or in pain and haven't passed the baby...I'm gonna hold hope.. atleast