Chills And Body Aches After Surgical Abortion. Have Bleeding And Cramps. Chances Of Pregnancy?

I had a surgical abortion on March 27, 2013. Two days after the procedure, I had chills (no fever) and all over body aches. I was taking the antibiotics they prescribed. (Didn't know if it was a reaction or myalgia steakto the ciproflaxacin antibiotics). The aches and chills dissipated and went away the next day or so. I had medium bleeding and then a week after the procedure started getting bad cramps and passed some medium size clots. Since then I have been bleeding (red) with some small clots.. It will be 3 weeks and I am still having some bleeding and some mild cramping every now and then. I did call the clinic and was told everything should be fine... Today (almost 3 weeks), I took a HPT and the test line was very, very dark... darker than the control line. I have had other abortions in the past and by 3 weeks, the HPT lines were very very faint.. I never had bleeding for 3 weeks and I NEVER had any cramping for this long. Is this normal? Or chance of retained tissue? My follow up visit is in 2 days and I definitely want an ultra sound