HCG confusion

On Sunday 08/26/2018 has blood done it was at 50.9. Had bleeding when I wiped. Two days later on Tuesday 08/28/2018 it was at 103 and my doc said it’s doubled but minimally. So today Friday 08/31/2018 which is 3 days later they are at 309. And again said they have doubled but minimally. Come back on the 10th of September for another blood draw. I’m not bleeding at all anymore unless major activity or sex. My question is at my local pregnancy center today they told me I should be 5 weeks. I thought I was 4.5weeks are these levels bad or good and are the normal this low being “5weeks”?