Hcg not doubling

Hey, so I'm 5 weeks and 4 days along and had my labs done.

Monday:1523

Wednesday:1721

My level only went up by 198 in 48 hrs. I'm so scared it'll be a miscarriage. Dr said not to worry yet and we'll do another blood test on Monday. Anyone else have anything like this?

Update:

So had blood work done again today and it went up to 2368. I know it's not where it's "supposed" to be but the Dr said it was great and to try not to worry. Routine ultrasound scheduled for Tuesday so we'll see what that brings. 🙂