IB or Early Period

Period (?) came 6 days early:

Friday: Dark brown spotting

Saturday: Medium flow, dark brown turning to bright red

Sunday: Lighter flow, bright red and light brown

Monday: Light dark brown

Tuesday: Dark brown spotting.

Saturday and Sunday were both heavy enough to warrant tampons and they were mostly filled. Took an early response test after my period was predicted to start and it was negative. Not TTC at all. On the pill and use condoms always. Thoughts?