I Had A Medical Abortion On The 30 Of June

I had a medical abortion on the 30 of June 2016 about 3 days after I start bleeding for at least 4 days. Two weeks after I went to the doctor to do an ultrasound to see if every thing had come out an yes the ultrasound show that its clear. I went to doctor about 2 week in August because of how am feeling an why no period as yet an he said true the termination of pregnancy that why am still having those feelings so I said OK. But till now am not seeing any period, am having pain, I have a big Tommy yet still they are saying am not pregnant. Can you plz give me an advice or tell me what happing to me