HCG - So confused

Hey y’all. I’m waiting to hear back from my doctor, but I’m super confused. I feel like I’m going to have a miscarriage but my doctor won’t just come out and say that’s what could be happening.

HCG Levels

12/28 - 61. (also first clear positive test)

12/30 - 95

1/6 - 956. - My doctor said this was reassuring and I thought things were fine.

I had an ultrasound on Monday and I was 6weeks/6days. They said I barely had a gestational sack and looking like barely 4 weeks.

1/17 - 894. After the ultrasound and seeing this, I thought for sure inevitable miscarriage.

1/18 - 990. Now it went back up. But still not much higher than a few weeks ago. Definitely didn’t double. Is a miscarriage still likely then??