Am I seeing this right?!

I had a chemical pregnancy last cycle. I was due for my period on Friday and I haven’t got anything so decided to take a test to see what happens. Can this really happen so fast?! Ive had some dark brown spotting when I wipe the last couple days but that’s it. I know it’s not from the chemical because my HCG was 0 with my last blood test. Anyone else experience a healthy pregnancy right after a chemical?