If i have low hcg levels, does that mean i am going to have a miscarriage?

No: Hcg alone cannot tell one they are going to miscarry. In early pregnancy the HCG should double every 2-3 days. If it is falling, or is not rising substantially over time, it is likely that there is a problem with the pregnancy (impending or current miscarriage, ectopic pregnancy). Once there is a visible pregnancy on ultrasound, hcgs have little value, and the ultrasound is more meaningful.