Just because your egg implanted outside of the uterus does not mean that your body is not producing hCG, though in an ectopic pregnancy that is resolving itself (through miscarriage), the levels of this hormone will drop over time. Having said that, watching out for symptoms of ectopic pregnancy could make all the difference to any pregnant woman. More treatment options will be available in the earlier stages of an ectopic pregnancy. Low hCG levels are sometimes responsible for a false negative pregnancy test. If your symptoms are screaming "I am pregnant!", especially with a missed period, but your test came up negative, contacting your doctor is the best approach. Although waiting another week, and then repeating your home pregnancy test might give you the same results.
Low hCG levels are not necessarily a sign that anything is wrong with your pregnancy. Your body could just be taking longer to produce this hormone in the first place. With ectopic pregnancies, pregnancy tests would typically show a positive result early on, but if you repeat the test later, as your hCG levels are dropping, it might then become negative. But again, if you are experiencing symptoms that worry you, call your doctor. You might not have an ectopic pregnancy, but something else could still be wrong, especially if you are in pain. If you do need treatment, you will be glad you called!