Pregnancy after miscarriage

Is it possible to get pregnant with leftover hcg in your system?? I had a natural miscarriage that started 9/26 and ended 10/3. The bleeding completely stopped but i took a pregnancy test and there is still a light line there. My levels were 13,900 on the 26th and dropped to 8,900 on the 27th. Havent had them tested since then. I wanted to try right away