EDD help!

Hi! I want help figuring out how far I actually am! I miscarried Sept 28 at 8w3d, and (finally) had my period on Nov 18. I took hpt on Dec16, 23, and 29. All were negative. I took another one this morning (Jan 4) and it came in positive very quickly! I know usually you calculate by your last period but testing positive on Day 48 seems like it would skew any “timing” using my last period. How far realistically am I?