Bleeding a week after finishing period?

Added the picture so you can see what the time line is like, but I started bleeding yesterday morning. I put a tampon in as I thought it was another period coming on, which has happened once or twice before.

I’ve used a tampon 3 times so far, but when I removed the tampons, it’s been browny coloured discharge mainly, with small blood clots. One of the tampons was real dark brown blood with clots.

I’ve resorted to using pads now as it wasn’t filling up any tampons, and it’s been mainly dark brown, almost black blood 👀

Does anyone know what the reason could be?? 😩😩😩