Implantation bleeding or AF??

Rebecca • Mammy of two amazing babies! Dylan and Esmé 💜💜
Hi ladies hopping you can help me out. I'm due AF today and thought she was showing her mean self but I've only gotten some dark brown discharge when I wipe (sorry TMI) and the smallest spot of red. I took a test Wednesday when glow told me too but it was negitive. Any help would be brilliant x