conceiving as soon as a week after an abortion?

I had an abortion november 17 2011I bled for a day or two after the procedure and then I was fine. November 25 2011 I had unprotected sex.  The 29th of november I started spotting it was never consistently flowing and I had no cramping and it didnt feel anything like a period. So I even went to the emergency room the next night and they checked me out by doing a pelvic exam and untrasound. Everything was normal and there were no remains. They said I was just having a normal period however the bleeding stopped the next day. I am worried the bleeding might have been implantation bleeding because I am expierencing some of the same symptoms I did before I found out I was pregnant. (fatigue, back aches and a little nausea)