What Could Bleeding, Thick Brown Discharge And Severe Abdominal Pain Indicate?

could this be a miscarriage or something? I had a period may 13 I thought I was done cause it was gone on may 16 but on the 18 when I went to the restroom I had blood on the tissue allot them it stopped a couple days later then I started having dark brown discharge badly kind of thick and i'm stilling having it.I also been waking up out of my sleep in excruciating pain in the mornings buggy it goes away.my tubes were tied in 1999. What could this Be?