13 weeks pregnant and and bled a few days ago

On Monday out of no where when I went pee I had a gush of red blood. I kept checking as I was waiting for my doctor to call me and it was getting darker and less. By the time I got to the Er it was brown. I had an ultrasound done then and again on Tuesday and my baby girl is completely fine and my cervix is closed and placenta is good. They could not figure out what happened and why. The nurse yesterday said the brown can still come out for a few days. Its more like coffee grounds now and not very much. So here 4 days later and a little bit more is coming out but I realized when I go number 2 more comes out..? Why is that? Is it because it’s pushing on/against it or something else? Anyone had this happen and how long did the brown coffee grounds like blood last? Again it’s not very much every time I wipe but sometimes more than others.