I’m so confused!?

This is my story- I had a missed miscarriage at 8 weeks on February 20th. I got pregnant right after and got a BFP March 26th. When I went to doc she think I’m only 4.5 wks pregnant but my app says 6wks today. I stafted spotting and then bleeding heavily the day after my Pap test. When I told my doc she said this would be an extremely early miscarriage and sent me for beta HCG bloodwork. I’m just confused if this is considered a miscarriage/chemical etc. My period was expected on March 26-27. Did anyone else bleed in very early pregnancy and everything was fine or is this another miscarriage? I feel perfectly fine. Very minimal cramping.