What Causes Intermittent Brown Discharge After An Abortion?

I inserted 4 mesoprostol and swallowed 2 to abort 3wks pregnancy and I bleed and discharged clots for 9days, on the 12th day, I had intercourse with my husband and each day my pant would be stained with brown discharge as if its old remaining blood and I was having feelings in my abdomen like period trying to come Out . After 20 days I went for pt test with blood and it was positive, as that time itwas still dropping red and my doctor sent me for scan and nothing was found in wall and inside the womb, on the 6the WK, I had sex with my husband and it came out and lasted for 4days but I am still discharging brownish that looked like old blood and am still having the feeling in my abdomen and another test now still reads positive and doctor said it might be the remaining, please am I pregnant or not.