The number itself (they are testing your HCG level) doesn't mean as much as whether or not it doubles within 48-72 hours. So hopefully your OB will order a second draw so you can see how your HCG is rising.
FWIW, the E.R. will almost always diagnose you with a "threatened miscarriage." You're really better off calling your OB and waiting to see what they say. I know bleeding/cramping can be scary, but it can also be totally normal. I'm assuming you haven't seen your OB yet, but the general rule is to worry if you're filling a pad an hour bleeding-wise.
Hope everything turns out fine with you and baby!