hcg levels

Sarah • Married. Beautiful baby girl July 2016. Miscarriage October 2017. TTC again.

I've seen a lot of postings about hcg levels and I feel like everyone else's are way higher than mine? last week around 4weeks mine was 28 and then 2 days later 78.

I see other peoples posts and the at 4 end was like 1247?? why is mine so low??