Chart shows i spotted dark brown to light brown 12/14-12/17 (period was due 12/17) After I got my positives(first light pregnancy test 12/21)

Soo

A week later or so from the brown spotting I started spotting brown followed by red bleeding (doesn't cover whole pad) on 12/25-now.

today(now) I took a test & it's darker then the tests I took before I started bleeding idk what's going on??? Does this happen during early pregnancy? Last period was 11/16.

What do you guys think ?