So, I was supposed to start my period about 5 days ago. On Thursday I thought I had started AF bc I was spotting a tan-ish discharge (which is usually how all my periods begin). It has gotten thicker in texture and it's dark brown now. Tomorrow is my 4th day, my periods usually last about 6 days. I don't think it really fits the description of implantation bleeding.

What the heck could this be? Has this happened to anyone else?