Odd scenario with slow rising hCG levels and spotting

Angie

My first date of last period was March 23 - so I’m supposedly 6 weeks along.

We began lab work for hCG levels with spotting last week, which has remained the same level of mild spotting and no pain:

1st hcg 5/2/2019 am: 74 --\> 2nd hcg 5/4/2019 am: 107 (48 hrs, 44% increase) --\> 3rd hcg 5/6/2019 am: 178 (48 hrs, 66% increase)

So in a week, my increase in the HCG level is a 66% increase from 2 days ago. If this were an ectopic pregnancy, the doctor says we generally see a \< 35% increase, and if this were miscarriage they would anticipate we would start seeing a decline in hcg.

I am so anxious what this means, going to keep checking hCG levels every two days and probably have an ultrasound later this week 🤷🏻‍♀️🧐🥺

Is this just an inevitable miscarriage, or will the numbers shoot up?