Low hcg at 5 weeks?

Courtney • 24 years old. Son born 5.4.14. TTC #2 :)
Has anyone had low hcg at 5 weeks pregnant? At 5 w 1 d my level was 722. At 3 w 6 d I had hcg of 14. I read that if you have a higher bmi, lower hcg is normal but just looking for some reassurance.