I have been spotting for 10 days it’s always brown or very dark red in colour, it goes from being very light (almost disappears) to heavy (but not like a period)

Everywhere I look for advice it says things about implantation bleeding and pregnancy, I took a test two days ago and it was negative

My period was due 4 days ago and by then I had already been spotting for 6 days

Any advice or helpful suggestions?

Edit: I am not on birth control and haven’t been for over 2 years and have never experienced anything like this before, I don’t think I’m pregnant I’m just seeking advice to see if any other woman have gone through this