Positive pregnancy test after period?!?

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I had a D and C on December 19th. I tested negative on January 16th and 19th and then started what I thought was my period on January 21st. I need for a couple of days and then it stopped. It was an unusually short period. I had a weird feeling and took a pregnancy test yesterday and it was positive. Am I pregnant or did I miscarry again on the 21st?

My doctor is doing bloodwork today and again in two days to see if HCG is doubling- I'm just looking for some opinions or seeing if anyone else has experienced this and what the outcome was. TIA.