Feeling nervous

Have been doing my hcg levels due to having a miscarriage back in April. I was on cloud nine. Did my levels last wedensday and they were 8,500 on Friday they were 11,000. Just got a call today right before going into work that the doctor was concerned about them not rising enough and that I need to come in on Thursday for an ultrasound. I don't know how to feel. This is what happened last time, except then I had bleeding. I went to the ultrasound appointment waited for 2 hours and them got the horrible news........I'm dreading this Thursday. I have been so excited with this pregnancy my numbers have been great, I've been feeling good.......now I feel like all the wind has been knocked out of me.