Monday will be four weeks since I had a miscarriage at 12 weeks pregnant with twins

I had HCG blood work on October 19 it was 343.1 then the Dr had me come in on October 21 and it had dropped to 179.9 that's the last time I had it checked I was curious if it had gone back to negative levels yet so today November 4th at 5 pm I took a Walmart $0.88 test and it was faintly pink positive.

My question is could my rate of HCG dropping have slowed down to where I could still be above a negative level or could this possibly be the start of a new pregnancy? Thanks for your input