Postpartum period

I had my first postpartum period June 5th (18 months pp still breastfeeding once at night) well it was heavy but pretty normal lasted 6 days and then done. But starting CD 14 I’ve had brown spotting. Only enough to wear a pantry liner but it’s been 6 days and I’m still having this brown spotting with no let up. Anyone know if this is normal/why this might be happening?

Not on any birth control and I’m not pregnant I took a test to be sure even though that’s basically impossible considering my period was only 2 weeks ago.