PLEASE READ & HELP !!

HELP PLEASE !! I just took this test just to make sure my HCG levels were at 0 , of course it’s neg. thaat’s not what I need help with. ————I have been having light (brown) spotting for the past couple of days (when I wipe) this morning I went to the bathroom and I wipe and there is a piece of tissue on the toilet paper , & now I’m cramping WHAT CAUSES THIS ???

* I will post a —google image— of something similar to what it looked like*

My miscarriage was exactly 25 days ago.

I am not on birth control & I haven’t started a regular period yet ! Any ideas???