Left over hcg?

Sydni

I’m almost 6 weeks post D&C; due to a missed miscarriage at 10 weeks. At first I thought this test was finally negative, i go back to look at it a little later and there’s a faint line. Could this STILL be left over hcg and if so how much longer should I wait before getting a negative.

p.s. during weeks 3&4 post D&C; we had lots of long hot sex using pull out method only twice