Pregnancy after miscarriage?

So I miscarried about a month ago. I took a pregnancy test and it was really dark positive. A week later I went to the doctor and the line was super light practically gone. So she said negative. I took a test the next day, negative.. no line at all. I took a test today about 8 days after my negative and it’s positive again. Faint positive but its noticable, much darker than the last test. Is it possible for hcg to fluctuate like that or can this be a new pregnancy?? Any help appreciated in advance 😘