I have read so many different things and I'm trying not to worry, but my dr didn't sound very optimistic. Has anyone else experienced something similar......

I went in this past Monday for my first indoc appt and they confirmed my pregnancy with a urine sample. I had an early miscarriage at the beginning of last month so that is the date we used for the expected due date. It would have put me about 5 weeks at that point. They checked my levels on Monday and they were 11,000. I went back on Wed and they increased to 15,000 (which my doctor said they would've liked to see the number doubled). I went in for a sonogram yesterday (given my last MC and that my numbers didn't double) and they saw a sac but no baby. I went back in on Friday to recheck my levels but since it was Friday I won't hear anything until Monday. I'm upset because she was leaning towards that I will miscarry again. Has anyone had a successful pregnancy with slow increasing levels like this?