Positive pregnancy test after miscarriage

I had to have a D&C May 31st because of a missed miscarriage. When I had the surgery I should have been 10 weeks and 4 days. The baby only measured at 6 weeks and 1 day.

1st doctors appointment levels were at 58,000

2nd appointment 10 days later levels dropped to 51,000

3rd appointment 5 day later my levels had dropped to 20,000.

I had the surgery 3 days later because I was on the verge of being septic and I have no idea what my levels were that day. With how fast they were dropping, I would think there would be no more HCG present in my body.

I took a pregnancy test on Monday and it came back with a faint positive and I’m just trying to figure out if this is residual HCG left in my body after the miscarriage, or am I pregnant again?