Pregnancy test

Bella • 18 years old❤Due date 11/02/2015 ❤
Okay so I know I'm pregnant.My blood and ultrasound have confirmed it but I had two tests left from when I first bought them so I took them just to see and my lines are alot lighter than the control lines...I am exactly 8 weeks pregnant today...Do you think my hcg levels are low?Is it bad?