Low rising HCG

I first when in on the 8th, my levels were 669. On the 11th and they went up to 710. I had an ultrasound done that day and there was a sac in my uterus so it’s most liking not a

Ectopic pregnancy.

Today I’m at 865. I go in again on Friday for an ultrasound and more blood work. My doctor keeps saying he doesn’t think it’s a good pregnancy. I’ve read that slow rising HCG levels had be normal. I’m just curious if anyone has had slow rising HCG levels and how it turned out for you.