I need help! miscarriage??

I went to the doctor a week and a half ago and had an ultrasound, with an empty sack, which meant we still weren't able to for sure determine how many weeks I was but guessed about 5 to 6 weeks. 
I woke up this morning, went to the restroom, wiped and had a really dark/blood like discharge, my doctor had me go the ER just to be safe. 
My pregnancy hormones have went from 4,000 to 9,100 in a week and a half and all of my other blood work seemed to be great. 
But the ultrasound at the ER, measured my sack at 5 weeks and 2 days, and its still an empty from a week and a half ago which lead the ER doctor to tell me he believes I'm having a miscarriage. 
The ultrasound lady at the ER was super fast and did not want to be there.
He said with my hormones rising that there's still hope.
I am so confused.